SAT Math : How to find value with a number line

Study concepts, example questions & explanations for SAT Math

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Example Questions

Example Question #11 : Number Lines And Absolute Value

Gre12

If the tick marks are equally spaced on the number line above, what is the average (arithmetic mean) of x, y, and z?

Possible Answers:

8

7

6

5

4

Correct answer:

6

Explanation:

First, we must find out by how much they are spaced by. It cannot be 1, since 4(4) = 16, which is too great of a step in the positive direction and exceeds the equal-spacing limit. 2 works perfectly, however, as 4(2) equals 8 and fits in line with the equal spacing.

Next, we can find the values of x and y since we are given a value of 6 for the third tick mark. As such, x (6 – 4) and y (6 – 2) are 2 and 4, respectively.

Finally, z is 4 steps away from y, and since each step has a value of 2, 2(4) = 8, plus the value that y is already at, 8 + 4 = 12 (or can simply count).

Finding the average of all 3 values, we get (2 + 4 + 12)/3 = 18/3 = 6.

Example Question #2 : Number Line

How many numbers 1 to 250 inclusive are cubes of integers?

Possible Answers:

5

4

6

7

8

Correct answer:

6

Explanation:

The cubes of integers from 1 to 250 are 1, 8, 27,64,125,216.

Example Question #1 : Number Line

Slide1

On the number line above, the tick marks are equally spaced. Which of the following expresses  in terms of ?

Possible Answers:

Correct answer:

Explanation:

If  is between  and  on the number line, then  and .

So  must be correct because 

.

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