finish this # pattern?

Question

a.25,(blank),61,(blank
b.87,(blank),43,(blank)
c.21,(blank),49,(blank)
d.64,(blank),(blank),(blank),32

Answer 1

If these are arithmetic progressions I would guess the answers would be:

a. 25, 43, 61, 79 (add 18 each time)
b. 87, 65, 43, 21 (subtract 22 each time)
c. 21, 35, 49, 63 (add 14 each time)
d. 64, 56, 48, 40, 32 (subtract 8 each time)

The easiest way is to figure out the average of the two numbers and put that in the middle.

For example in the first one:
25, ___, 61, ___

The average of 25 and 61 is:
= (25 + 61) / 2
= 86 / 2
= 43

So put that in:
25, 43, 61, ___

Now you can see the pattern is add 18 each time...
25, 43, 61, 79

It's a similar thing with b and c.

For d, you have 64 and 32. The average is 48. So put that in the middle:
64, ___, 48, ___, 32

Repeat this for the two other blanks:
= (64 + 48) / 2
= 112 / 2
= 56

64, 56, 48, ___, 32

= (48 + 32 ) / 2
= 80 / 2
= 40
64, 56, 48, 40, 32

Please let me know if this method helps you solve these problems. I'm more interested in teaching you how to solve these type of problems than just giving the answers. If you need more help, just post a comment under your question.

Answer 2

GIRL.....I SUCK IN MATH!, HOWEVER, I'M CUTE.