Question

What will come in the place of question mark (?) in the following number series?

60, 70, 83, 102, 130, 170, ?

1. 220
2. 325
3. 225
4. 125
5. None of these

Answer 1

Correct Answer - Option 3 : 225

Given:

60, 70, 83, 102, 130, 170, ?

Calculation:

From the above series, the logic can be explained as

70 - 60 = 10

83 - 70 = 13

102 - 83 = 19

130 - 102 = 28

170 - 130 = 40

? - 170 = let's say x

Taking the double difference

13 - 10 = 3

19 - 13 = 6

28 - 19 = 9

40 - 28 = 12

By observing the pattern of double difference we can say

x - 40 = 15

⇒ x = 55

So, ? - 170 = 55

⇒ ? = 225

∴ The value of ? will be 225.