SAT Math : Evaluating Expressions

Study concepts, example questions & explanations for SAT Math

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Example Questions

Example Question #31 : Expressions

Let , what is the value of ?

Possible Answers:

Correct answer:

Explanation:

Example Question #41 : Expressions

Tim went to the hardware store to buy nails and screws.  The screws were being sold for $.07 each and the nails were being sold in packs of 40 for $1.30.

If Tim spent $14.80, how many nails did he buy?

Possible Answers:

Correct answer:

Explanation:

Nails are sold in packs of 40 for $1.30.

Screws are $0.07 each.

Since the total is $14.80, we must have a 0 in the hundredths place.  This means that the number of screws must be a multiple of 10 (otherwise it won't be a 0).  Now we are essentially dealing with screws in packs of 10 for $0.70.

Now we have 5 values of  to check.  If  is divisible by 7, then we have the right answer.

What we find is that for  is divisible by 7.

Thus our answer is 6 boxes or 240 nails.

Example Question #2513 : Sat Mathematics

Twenty percent of a number, , is four greater than the product of that number and six. Which of the following algebraic equations could be used to find ?

Possible Answers:

Correct answer:

Explanation:

The "is" in the question means "equal," so whatever comes before "is" must be equal to whatever comes after. We will find an expression for the information before "is" and an expression for the information after "is," and then we will set these two expressions equal.

Twenty percent of a number can be represented as 0.2n, because 20% expressed as a decimal is 0.2, and because twenty percent "of" a number means the product of that number and twenty percent.

Four greater than the product of a number and six means that we must first find the product of that number and six, and then increase this value by 4.

The product of a number and six means that we must multiply this number by six, which can be represented by 6n. Increasing 6n by 4 can be modeled by the expression 6n + 4, or 4 + 6n (because of the commutative property of addition).

Setting the two expressions equal gives us 0.2n = 4 + 6n .

Example Question #2514 : Sat Mathematics

Based on the chart, which equation represents the table data?

 

Possible Answers:

Correct answer:

Explanation:

The easiest way to solve this problem is to guess-and-check the answer choices. The equation that can be used to match the table will be correct.

We can see that the values in the table match the equation for each given value. Thus, this must be our answer.

We can also determine certain characteristics from the table itself. For example, as x increases, y(x) decreases. This tells us that there is likely a negative coefficient, which can help narrow down the answer options.

Example Question #1071 : Psat Mathematics

An elementary school class consists of  boys and  girls. What fraction of the class is female?

Possible Answers:

Correct answer:

Explanation:

There are B+G total students in the elementary school class, so G out of B+G are girls.

Example Question #2516 : Sat Mathematics

What is the sixth term of the sequence: \frac{1}{3}, \frac{1}{2}, \frac{3}{4}, \frac{9}{8} ... ?

Possible Answers:

\frac{27}{16}

\frac{81}{16}

\frac{81}{32}

2

\frac{3}{2}

Correct answer:

\frac{81}{32}

Explanation:

Each term equals the previous term multiplied by \frac{3}{2}.

The fifth term in the sequence is \frac{9}{8} \cdot \frac{3}{2} = \frac{27}{16}.

The sixth term in the sequence is thus \frac{27}{16} \cdot \frac{3}{2} = \frac{81}{32}.

Example Question #2517 : Sat Mathematics

If \dpi{100} \small z-3=n, then \dpi{100} \small 2z=  ?

Possible Answers:

\dpi{100} \small 2n+6

\dpi{100} \small n

\dpi{100} \small n+3

\dpi{100} \small 3n+6

\dpi{100} \small n+6

Correct answer:

\dpi{100} \small 2n+6

Explanation:

Begin by rearranging the equation to solve for z:

\dpi{100} \small z=n+3

This means that \dpi{100} \small 2z=2\left ( n+3 \right ), which can be rewritten as \dpi{100} \small 2n+6.

Example Question #741 : Algebra

If  , what is the value of  ?

Possible Answers:

Correct answer:

Explanation:

First, solve the equation  to find  .

If , then  must equal  .

 

Then, plug the value for  into the second equation, .  

.

Example Question #2511 : Sat Mathematics

Which of the following is a correct statement?

Possible Answers:

Correct answer:

Explanation:

 

Similarly,  and .

 

Using some substitution:

Multiply:

Example Question #31 : Evaluating Expressions

Possible Answers:

Correct answer:

Explanation:

The purpose of this question is to practice using the correct order of operations, which is the proper way to simplify this expression. Using PEMDAS (parentheses, exponent, multiplication, division, addition, subtraction) the exponent is treated first,

then the multiplication,

and the addition operation is handled last.

Executing the exponent simplifies the expression to 

,

then executing the multiplication simplifies the expression to 

,

which adds together to be .

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