PSAT Math : How to find value with a number line

Study concepts, example questions & explanations for PSAT Math

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Example Questions

Example Question #12 : 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:

4

6

5

8

7

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 #1 : How To Find Value With A Number Line

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

Possible Answers:

5

6

7

8

4

Correct answer:

6

Explanation:

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

Example Question #3 : How To Find Value With A Number Line

Numberline_1

Refer to the above number line. Which of the points is most likely the location of the number  ?

Possible Answers:

Correct answer:

Explanation:

, so 

Therefore, 

On the number line,  appears between 0.3 and 0.4 and is the correct choice.

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