ISEE Lower Level Quantitative : Prime Numbers

Study concepts, example questions & explanations for ISEE Lower Level Quantitative

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Example Questions

Example Question #2721 : Isee Lower Level (Grades 5 6) Quantitative Reasoning

Which of the following is the product of two distinct prime numbers? 

Possible Answers:

\(\displaystyle 36\)

\(\displaystyle 6\)

\(\displaystyle 1\)

\(\displaystyle 8\)

Correct answer:

\(\displaystyle 6\)

Explanation:

There are two key terms in this question that we need to understand in order to answer the question correctly: product and prime numbers. 

Product is the answer to a multiplication problem. 

Prime numbers are numbers that are greater than \(\displaystyle 1\) and only have factors of the number \(\displaystyle 1\) and itself. For example \(\displaystyle 3\) is a prime number because it's greater than \(\displaystyle 1\) and the factors of \(\displaystyle 3\) are only \(\displaystyle 1\) and \(\displaystyle 3\)

To find the correct answer, we need to know the factor pairs for our answer choices. The correct answer will have a factor pair of two prime numbers. 

Let's look at our answer options:

\(\displaystyle 1\)- from our definition of a prime number we know that \(\displaystyle 1\) cannot be correct because prime numbers are greater than \(\displaystyle 1\)

\(\displaystyle 8\)- A factor pair for \(\displaystyle 8\) is \(\displaystyle 2\times 4\). Though \(\displaystyle 2\) is a prime number, \(\displaystyle 4\) is not. 

\(\displaystyle 36\)- A factor pair for \(\displaystyle 36\) is \(\displaystyle 6\times6\), and \(\displaystyle 6\) is not a prime number. 

\(\displaystyle 6\)- A factor pair for \(\displaystyle 6\) is \(\displaystyle 2\times3\). Both \(\displaystyle 2\) and \(\displaystyle 3\) are prime numbers, thus \(\displaystyle 6\) is our correct answer. 

Example Question #2722 : Isee Lower Level (Grades 5 6) Quantitative Reasoning

Which of the following is the product of two distinct prime numbers?

Possible Answers:

\(\displaystyle 8\)

\(\displaystyle 12\)

\(\displaystyle 33\)

\(\displaystyle 2\)

Correct answer:

\(\displaystyle 33\)

Explanation:

There are two key terms in this question that we need to understand in order to answer the question correctly: product and prime numbers.

Product is the answer to a multiplication problem.

Prime numbers are numbers that are greater than and only have factors of the number and itself. For example is a prime number because it's greater than and the factors of are only and .

To find the correct answer, we need to know the factor pairs for our answer choices. The correct answer will have a factor pair of two prime numbers.

Let's look at our answer options:

\(\displaystyle 2\)- A factor pair for \(\displaystyle 2\) is \(\displaystyle 1\times 2\), and \(\displaystyle 1\) is not a prime number.

- A factor pair for is . Though is a prime number, is not.

\(\displaystyle 12\)- A factor pair for \(\displaystyle 12\) is \(\displaystyle 6\times2\), and is not a prime number.

\(\displaystyle 33\)- A factor pair for \(\displaystyle 33\) is \(\displaystyle 11\times3\). Both \(\displaystyle 11\) and are prime numbers, thus \(\displaystyle 33\) is our correct answer.

Example Question #2723 : Isee Lower Level (Grades 5 6) Quantitative Reasoning

Which of the following is the product of two distinct prime numbers?

Possible Answers:

\(\displaystyle 12\)

\(\displaystyle 8\)

\(\displaystyle 33\)

\(\displaystyle 2\)

Correct answer:

\(\displaystyle 33\)

Explanation:

There are two key terms in this question that we need to understand in order to answer the question correctly: product and prime numbers.

Product is the answer to a multiplication problem.

Prime numbers are numbers that are greater than and only have factors of the number and itself. For example is a prime number because it's greater than and the factors of are only and .

To find the correct answer, we need to know the factor pairs for our answer choices. The correct answer will have a factor pair of two prime numbers.

Let's look at our answer options:

\(\displaystyle 2\)- A factor pair for \(\displaystyle 2\) is \(\displaystyle 1\times 2\), and \(\displaystyle 1\) is not a prime number.

- A factor pair for is . Though is a prime number, is not.

\(\displaystyle 12\)- A factor pair for \(\displaystyle 12\) is \(\displaystyle 6\times2\), and is not a prime number.

\(\displaystyle 33\)- A factor pair for \(\displaystyle 33\) is \(\displaystyle 11\times3\). Both \(\displaystyle 11\) and are prime numbers, thus \(\displaystyle 33\) is our correct answer.

Example Question #2724 : Isee Lower Level (Grades 5 6) Quantitative Reasoning

Which of the following is the product of two distinct prime numbers?

Possible Answers:

\(\displaystyle 8\)

\(\displaystyle 35\)

\(\displaystyle 16\)

\(\displaystyle 40\)

Correct answer:

\(\displaystyle 35\)

Explanation:

There are two key terms in this question that we need to understand in order to answer the question correctly: product and prime numbers.

Product is the answer to a multiplication problem.

Prime numbers are numbers that are greater than and only have factors of the number and itself. For example is a prime number because it's greater than and the factors of are only and .

To find the correct answer, we need to know the factor pairs for our answer choices. The correct answer will have a factor pair of two prime numbers.

Let's look at our answer options:

- A factor pair for is . Though is a prime number, is not.

\(\displaystyle 16\)- A factor pair for \(\displaystyle 16\) is \(\displaystyle 4\times4\), and \(\displaystyle 4\) is not a prime number.

\(\displaystyle 40\)- A factor pair for \(\displaystyle 40\) is \(\displaystyle 10\times4\), and both \(\displaystyle 10\) and \(\displaystyle 4\) are not a prime numbers.

\(\displaystyle 35\)- A factor pair for \(\displaystyle 35\) is \(\displaystyle 5\times 7\). Both \(\displaystyle 5\) and \(\displaystyle 7\) are prime numbers, thus \(\displaystyle 35\) is our correct answer.

 

 

Example Question #2725 : Isee Lower Level (Grades 5 6) Quantitative Reasoning

Which of the following is the product of two distinct prime numbers?

Possible Answers:

\(\displaystyle 18\)

\(\displaystyle 10\)

\(\displaystyle 20\)

\(\displaystyle 12\)

Correct answer:

\(\displaystyle 10\)

Explanation:

There are two key terms in this question that we need to understand in order to answer the question correctly: product and prime numbers.

Product is the answer to a multiplication problem.

Prime numbers are numbers that are greater than and only have factors of the number and itself. For example is a prime number because it's greater than and the factors of are only and .

To find the correct answer, we need to know the factor pairs for our answer choices. The correct answer will have a factor pair of two prime numbers.

Let's look at our answer options:

- A factor pair for  is , and  is not a prime number.

\(\displaystyle 18\)- A factor pair for \(\displaystyle 18\) is  \(\displaystyle 3\times6\), and \(\displaystyle 6\) is not a prime number.

\(\displaystyle 20\)- A factor pair for \(\displaystyle 20\) is \(\displaystyle 5\times4\), and \(\displaystyle 4\) is not a prime number.

\(\displaystyle 10\)- A factor pair for \(\displaystyle 10\) is \(\displaystyle 2\times 5\). Both and \(\displaystyle 5\) are prime numbers, thus \(\displaystyle 10\) is our correct answer.

Example Question #2726 : Isee Lower Level (Grades 5 6) Quantitative Reasoning

Which of the following is the product of two distinct prime numbers?

Possible Answers:

\(\displaystyle 30\)

\(\displaystyle 1\)

\(\displaystyle 12\)

\(\displaystyle 21\)

Correct answer:

\(\displaystyle 21\)

Explanation:

There are two key terms in this question that we need to understand in order to answer the question correctly: product and prime numbers.

Product is the answer to a multiplication problem.

Prime numbers are numbers that are greater than and only have factors of the number and itself. For example is a prime number because it's greater than and the factors of are only and .

To find the correct answer, we need to know the factor pairs for our answer choices. The correct answer will have a factor pair of two prime numbers.

Let's look at our answer options:

- from our definition of a prime number we know that cannot be correct because prime numbers are greater than .

- A factor pair for  is , and  is not a prime number.

\(\displaystyle 30\)- A factor pair for \(\displaystyle 30\) is \(\displaystyle 5\times6\), and  is not a prime number.

\(\displaystyle 21\)- A factor pair for \(\displaystyle 21\) is \(\displaystyle 7\times3\). Both \(\displaystyle 7\) and are prime numbers, thus \(\displaystyle 21\) is our correct answer.

 

 

Example Question #2727 : Isee Lower Level (Grades 5 6) Quantitative Reasoning

Which of the following is the product of two distinct prime numbers?

Possible Answers:

\(\displaystyle 16\)

\(\displaystyle 8\)

\(\displaystyle 26\)

\(\displaystyle 32\)

Correct answer:

\(\displaystyle 26\)

Explanation:

There are two key terms in this question that we need to understand in order to answer the question correctly: product and prime numbers.

Product is the answer to a multiplication problem.

Prime numbers are numbers that are greater than and only have factors of the number and itself. For example is a prime number because it's greater than and the factors of are only and .

To find the correct answer, we need to know the factor pairs for our answer choices. The correct answer will have a factor pair of two prime numbers.

Let's look at our answer options:

- A factor pair for is . Though is a prime number, is not.

- A factor pair for  is , and  is not a prime number.

\(\displaystyle 32\)- A factor pair for \(\displaystyle 32\) is \(\displaystyle 4\times 8\), and both \(\displaystyle 4\) and \(\displaystyle 8\) are not a prime numbers.

\(\displaystyle 26\)- A factor pair for \(\displaystyle 26\) is \(\displaystyle 2\times13\). Both and \(\displaystyle 13\) are prime numbers, thus \(\displaystyle 26\) is our correct answer.

Example Question #2728 : Isee Lower Level (Grades 5 6) Quantitative Reasoning

Which of the following is the product of two distinct prime numbers?

Possible Answers:

\(\displaystyle 14\)

\(\displaystyle 44\)

\(\displaystyle 24\)

\(\displaystyle 40\)

Correct answer:

\(\displaystyle 14\)

Explanation:

There are two key terms in this question that we need to understand in order to answer the question correctly: product and prime numbers.

Product is the answer to a multiplication problem.

Prime numbers are numbers that are greater than and only have factors of the number and itself. For example is a prime number because it's greater than and the factors of are only and .

To find the correct answer, we need to know the factor pairs for our answer choices. The correct answer will have a factor pair of two prime numbers.

Let's look at our answer options:

\(\displaystyle 24\)- A factor pair for \(\displaystyle 24\) is \(\displaystyle 4\times6\), and both \(\displaystyle 4\) and \(\displaystyle 6\) are not prime numbers.

- A factor pair for  is , and both  and  are not a prime numbers.

\(\displaystyle 44\)- A factor pair for \(\displaystyle 44\) is \(\displaystyle 4\times11\), and \(\displaystyle 4\) is not a prime number. 

\(\displaystyle 14\)- A factor pair for \(\displaystyle 14\) is \(\displaystyle 2\times7\). Both and \(\displaystyle 7\) are prime numbers, thus \(\displaystyle 14\) is our correct answer.

 

 

 

Example Question #2729 : Isee Lower Level (Grades 5 6) Quantitative Reasoning

Which of the following is the product of two distinct prime numbers?

Possible Answers:

\(\displaystyle 1\)

\(\displaystyle 15\)

\(\displaystyle 12\)

\(\displaystyle 18\)

Correct answer:

\(\displaystyle 15\)

Explanation:

There are two key terms in this question that we need to understand in order to answer the question correctly: product and prime numbers.

Product is the answer to a multiplication problem.

Prime numbers are numbers that are greater than and only have factors of the number and itself. For example is a prime number because it's greater than and the factors of are only and .

To find the correct answer, we need to know the factor pairs for our answer choices. The correct answer will have a factor pair of two prime numbers.

Let's look at our answer options:

- from our definition of a prime number we know that cannot be correct because prime numbers are greater than .

- A factor pair for  is , and \(\displaystyle 6\) is not a prime number.

- A factor pair for  is , and  is not a prime number.

\(\displaystyle 15\)- A factor pair for \(\displaystyle 15\) is \(\displaystyle 3\times5\). Both \(\displaystyle 5\) and are prime numbers, thus \(\displaystyle 15\) is our correct answer.

 

Example Question #2730 : Isee Lower Level (Grades 5 6) Quantitative Reasoning

Which of the following is the product of two distinct prime numbers?

Possible Answers:

\(\displaystyle 12\)

\(\displaystyle 24\)

\(\displaystyle 55\)

\(\displaystyle 32\)

Correct answer:

\(\displaystyle 55\)

Explanation:

There are two key terms in this question that we need to understand in order to answer the question correctly: product and prime numbers.

Product is the answer to a multiplication problem.

Prime numbers are numbers that are greater than and only have factors of the number and itself. For example is a prime number because it's greater than and the factors of are only and .

To find the correct answer, we need to know the factor pairs for our answer choices. The correct answer will have a factor pair of two prime numbers.

Let's look at our answer options:

- A factor pair for  is , and  is not a prime number.

- A factor pair for  is , and both  and  are not prime numbers.

- A factor pair for  is , and both  and  are not a prime numbers.

\(\displaystyle 55\)- A factor pair for \(\displaystyle 55\) is \(\displaystyle 5\times11\). Both \(\displaystyle 5\) and \(\displaystyle 11\) are prime numbers, thus \(\displaystyle 55\) is our correct answer.

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