Series and Sequences

Fast trick to solve Series & sequences

What should come in the place of Question marks (?) in the following series?

1) 43 , 62 , 84 , 109 , 137 , ?

Lets check the difference between numbers-

62 - 43 =19

84 - 62 =22

109 - 84 =25

137 - 109 =28

The difference of the two consecutive numbers are- 19 , 22 , 25 , 28 ,

So it is clear that

(19 + 3) = 22

(22 + 3) = 25

(25 + 3) = 28

(28 + 3) = 31

so 137 + 31 = 168

? = 168


2) 2 , 7 , 8 , 9 , 9 , 12 , 17 , 18 , 19 , 19 ?

Lets check the difference between numbers-

7 - 2 = 5

8 - 7 = 1

9 - 8 = 1

9 - 9 = 0

12 - 9 = 3

17 - 12 = 5

18 - 17 = 1

19 - 18 = 1

19 - 19 = 0

As we see the the difference between numbers - 5 , 1 , 1 , 0 , 3
and repeate again- 5 , 1 , 1 , 0 so the next number will be 3

19 + 3 = 22

? = 22