ISEE Upper Level Quantitative : ISEE Upper Level (grades 9-12) Quantitative Reasoning

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

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Example Questions

Example Question #72 : Factors / Multiples

Which one is greater?

 

\displaystyle (a) The product of the two greatest prime numbers less than \displaystyle 50

\displaystyle (b)\ 2000

Possible Answers:

it is not possible to tell based on the information given.

\displaystyle (a) and \displaystyle (b) are equal

\displaystyle (a) is greater

\displaystyle (b) is greater

Correct answer:

\displaystyle (a) is greater

Explanation:

A prime number is a natural number greater than \displaystyle 1 that can be divided only by \displaystyle 1 and itself. The two greatest prime numbers less than \displaystyle 50 are \displaystyle 47 and \displaystyle 43.

 

So their product is:

 

\displaystyle 47\times 43=2021, which is greater than \displaystyle 2000. So \displaystyle (a) is greater than \displaystyle (b).

Example Question #73 : Numbers And Operations

Which one is greater?

 

\displaystyle (a) The sum of the prime numbers between \displaystyle 50 and \displaystyle 60

\displaystyle (b) The sum of the prime numbers between \displaystyle 55 and \displaystyle 65

Possible Answers:

\displaystyle (a) and \displaystyle (b) are equal

\displaystyle (b) is greater

it is not possible to tell based on the information given.

\displaystyle (a) is greater

Correct answer:

\displaystyle (b) is greater

Explanation:

A prime number is a natural number greater than \displaystyle 1 that can be divided only by \displaystyle 1 and itself.

 

The prime numbers between \displaystyle 50 and \displaystyle 60 are \displaystyle 53,59, so we have:

 

\displaystyle (a)=53+59=112

 

The prime numbers between \displaystyle 55 and \displaystyle 65 are \displaystyle 59, 61, so we have:

 

\displaystyle (b)=59+61=120

 

So \displaystyle (b) is greater than \displaystyle (a).

Example Question #21 : Prime Numbers

Which is the greater quantity?

(A) The sum of the even integers from 21 to 30 inclusive

(B) Three times the sum of the prime integers from 21 to 30 inclusive

Possible Answers:

(A) and (B) are equal

It is impossible to determine which is greater from the information given

(B) is greater

(A) is greater

Correct answer:

(B) is greater

Explanation:

The even integers from 21 to 30 inclusive are 22, 24, 26, 28, and 30; their sum is 

\displaystyle 22+24+26+28+30 = 130

The prime integers from 21 to 30 inclusive are 23 and 29. their sum is 

\displaystyle 23+29 = 52

and three times this sum is 

\displaystyle 3 \cdot 52 = 156

This makes (B) greater

Example Question #22 : Prime Numbers

What is the sum of the prime integers between 75 and 100?

Possible Answers:

\displaystyle 269

\displaystyle 274

\displaystyle 439

\displaystyle 351

\displaystyle 348

Correct answer:

\displaystyle 348

Explanation:

The prime integers between 75 and 100 are 

\displaystyle 79, 83, 89, 97

Their sum is 

\displaystyle 79 + 83+ 89+97 = 348

Example Question #23 : Prime Numbers

Which is the greater quantity?

(A) The number of composite integers between 41 and 50 inclusive.

(B) The number of prime integers between 41 and 50 inclusive.

Possible Answers:

(B) is greater

It is impossible to determine which is greater from the information given

(A) and (B) are equal

(A) is greater

Correct answer:

(A) is greater

Explanation:

The only prime numbers among the ten in the range 41 through 50 are 41, 43, and 47; this makes three prime numbers and seven composite numbers, so (A) is greater.

Example Question #23 : Prime Numbers

Multiply the least and greatest primes between 80 and 100.

Possible Answers:

\displaystyle 8,439

\displaystyle 7,553

\displaystyle 8,051

\displaystyle 7,719

\displaystyle 7,857

Correct answer:

\displaystyle 8,051

Explanation:

The least and greatest primes between 80 and 100 are 83 and 97; their product is 

\displaystyle 83 \times 97 = 8,051

Example Question #25 : Prime Numbers

Which of the following is the greater quantity?

(A) The sum of the prime numbers between 80 and 90

(B) The sum of the prime numbers between 90 and 100

Possible Answers:

It is impossible to determine which is greater from the information given

(A) is greater

(B) is greater

(A) and (B) are equal

Correct answer:

(A) is greater

Explanation:

The prime numbers between 80 and 90 are 83 and 89, whose sum is \displaystyle 83 + 89 = 172; the only prime number between 90 and 100 is 97. (A) is the greater quantity.

Example Question #26 : Prime Numbers

Which is the greater quantity?

(A) Twice the number of prime numbers between 41 and 50 inclusive

(B) The number of composite numbers between 41 and 50 inclusive

Possible Answers:

(A) is greater

(A) and (B) are equal

It is impossible to determine which is greater from the information given

(B) is greater

Correct answer:

(B) is greater

Explanation:

Out of the ten integers from 41 to 50, the prime numbers are 41, 43, and 47 - therefore, there are three prime numbers and seven composite numbers. Since

\displaystyle 2 \times 3 = 6 < 7,

(B) is greater.

Example Question #81 : Factors / Multiples

Which of the following is the greater quantity?

(A) The sum of the prime numbers between 50 and 60

(B) The sum of the odd composite numbers between 50 and 60

Possible Answers:

(A) and (B) are equal

(B) is greater

(A) is greater

It is impossible to determine which is greater from the information given

Correct answer:

(B) is greater

Explanation:

The prime numbers between 50 and 60 are 53 and 59; their sum is \displaystyle 53+59 = 112. The odd composite numbers between 50 and 60 are 51, 55, and 57; their sum is \displaystyle 51+55+57 = 163. Therefore, (B) is greater.

Example Question #31 : Prime Numbers

\displaystyle M and \displaystyle N are prime integers. \displaystyle 60 < M < 70 and \displaystyle 80 < N < 90. What is the minimum value of \displaystyle M + N ?

Possible Answers:

\displaystyle 146

\displaystyle 150

\displaystyle 144

\displaystyle 142

\displaystyle 148

Correct answer:

\displaystyle 144

Explanation:

The least prime integer between 60 and 70 is 61, so this is the minimum value of \displaystyle M. The least prime integer between 80 and 90 is 83, so this is the minimum value of \displaystyle N. Since 

\displaystyle M \geq 61 and \displaystyle N \geq 83,

then , by the addition property of inequality, 

\displaystyle M + N \geq 61 + 83 = 144.

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