PSAT Math : How to find the number of integers between two other integers

年代tudy concepts, example questions & explanations for PSAT Math

varsity tutors app store varsity tutors android store

Example Questions

Example Question #1 :How To Find The Number Of Integers Between Two Other Integers

A custom-made ruler is30\ cmlong and for every2\ cmthere's a tick mark. How many tick marks are there on the ruler?

Possible Answers:

17

16

15

14

18

Correct answer:

16

Explanation:

There will be 15 gaps of2\ cmlong but 16 tick marks because there will be a tick mark on each end of the ruler.

Example Question #1 :How To Find The Number Of Integers Between Two Other Integers

How many prime numbers are between 1 to 25?

Possible Answers:

Correct answer:

Explanation:

质数是一个ca的数量大于1n only be divided by 1 and itself. Simply count from 1 to 25 and see how many values fit the criteria.

2, 3,4,5,6,7,8, 9, 10,11,12,13,14, 15, 16,17,18,19,20, 21, 22,23,24, 25

Prime numbers are underlined. Nine prime numbers are in this set interval.

Example Question #1 :How To Find The Number Of Integers Between Two Other Integers

Four consecutive odd integers sum to 40. How many of these numbers are prime?

Possible Answers:

Correct answer:

Explanation:

Letxequal the smallest of the four numbers. Therefore:

\dpi{100} x + (x+2)+(x+4)+(x+6)=40

\dpi{100} 4x +12 = 40

\dpi{100} 4x + 28

\dpi{100} x=7

Therefore the four odd numbers are 7, 9, 11, and 13. Since all are prime except 9, three of the numbers are prime.

Example Question #1 :How To Find The Number Of Integers Between Two Other Integers

Find the median of this set of numbers

Possible Answers:

Correct answer:

Explanation:

To find the median of a set of numbers, we must first order them from smallest to greatest.

Next, we must find the number directly in the middle, which has an equal number of numbers to the right and to the left.

Therefore, our answer is.

Learning Tools by Varsity Tutors