HSPT Quantitative : How to work with number series

Study concepts, example questions & explanations for HSPT Quantitative

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Example Questions

Example Question #141 : Hspt Quantitative Skills

What number should come next in this series?

 __

Possible Answers:

\displaystyle 36

\displaystyle 18

\displaystyle 23

\displaystyle 29

Correct answer:

\displaystyle 23

Explanation:

The pattern is add \displaystyle 10, subtract \displaystyle 3. The last operation is \displaystyle 26-3=23.

Example Question #1 : How To Work With Number Series

What number should come next in this series?

\displaystyle 13, 10, 5, 2, 1, __

Possible Answers:

\displaystyle 0

\displaystyle 3

\displaystyle -2

\displaystyle \frac{1}{2}

Correct answer:

\displaystyle -2

Explanation:

The pattern is subtract \displaystyle 3, divide by \displaystyle 2. The last operation is \displaystyle 1-3=-2.

Example Question #143 : Hspt Quantitative Skills

What number should come next in this series?

\displaystyle 1, 4, 9, 16, 25, 36, __

Possible Answers:

\displaystyle 64

\displaystyle 49

\displaystyle 47

\displaystyle 39

Correct answer:

\displaystyle 49

Explanation:

The pattern in this series is perfect squares:

\displaystyle 1\cdot 1=1

\displaystyle 2\cdot 2=4

\displaystyle 3\cdot 3=9

...

\displaystyle 7\cdot 7=49

Example Question #144 : Hspt Quantitative Skills

What number should come next in this series?

\displaystyle .7, 1.2, 1.1, 1.6, 1.5, 2.0, __

Possible Answers:

\displaystyle 1.9

\displaystyle 2.1

\displaystyle 2.7

\displaystyle 2.5

Correct answer:

\displaystyle 1.9

Explanation:

The pattern is add \displaystyle .5, then subtract \displaystyle .1.

The last operation is \displaystyle 2.0-.1=1.9.

Example Question #145 : Hspt Quantitative Skills

What number should come next in this series?

\displaystyle 12, 6, 16, 8, 18, __

Possible Answers:

\displaystyle 19

\displaystyle 17

\displaystyle 9

\displaystyle 7

Correct answer:

\displaystyle 9

Explanation:

The pattern is divide by \displaystyle 2, then add \displaystyle 10. The last operation is \displaystyle 18\div 2=9.

Example Question #2 : How To Work With Number Series

What number should come next in this series?

\displaystyle 5, 21, 5, 19, 5, 17, 5, __

Possible Answers:

\displaystyle 21

\displaystyle -7

\displaystyle 15

\displaystyle 5

Correct answer:

\displaystyle 15

Explanation:

The general pattern for this one is subtract \displaystyle 2 each time, but a \displaystyle 5 is placed between each element. Ignoring the \displaystyle 5's, the last operation is \displaystyle 17-2=15.

Example Question #1 : How To Work With Number Series

What number should come next in this series? 

\displaystyle 34, 17, 14, 7, 4, __

Possible Answers:

\displaystyle 0

\displaystyle 2

\displaystyle 6

\displaystyle 1

Correct answer:

\displaystyle 2

Explanation:

The pattern is divide by \displaystyle 2, then subtract \displaystyle 3. The last operation is \displaystyle 4\div2=2.

Example Question #2 : How To Work With Number Series

What number should fill in the blank in this series?

\displaystyle .5,1.5,7.5,22.5,__\displaystyle ,85.5,91.5

Possible Answers:

\displaystyle 13.5

\displaystyle 28.5

\displaystyle 23.5

\displaystyle 26.5

Correct answer:

\displaystyle 28.5

Explanation:

The pattern is multiply by \displaystyle 3, then add \displaystyle 6. The operation before the blank is \displaystyle 22.5+6=28.5.

Example Question #5 : Number Series*

What number should come next in this series?

\displaystyle 1,3,6,10,15,__

Possible Answers:

\displaystyle 22

\displaystyle 20

\displaystyle 17

\displaystyle 21

Correct answer:

\displaystyle 21

Explanation:

Each element in the series adds a number that is one more than the last:

\displaystyle 1+2=3

\displaystyle 3+3=6

\displaystyle 6+4=10

\displaystyle 10+5=15

\displaystyle 15+6=21

Example Question #6 : Number Series*

What number should come next in this series?

\displaystyle 25,24,22,19,15,__

Possible Answers:

\displaystyle 10

\displaystyle 8

\displaystyle 14

\displaystyle 11

Correct answer:

\displaystyle 10

Explanation:

In this series, a number is subtracted each time. That number always increases by \displaystyle 1:

\displaystyle 25-1=24

\displaystyle 24-2=22

\displaystyle 22-3=19

...

The last operation is:

\displaystyle 15-5=10

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