Which of the following numbers will replace the question mark (?) in the given series?
24, 28, 35, 48, 73, ?

24, 28, 35, 48, 73, ?

Difference of two constitutive number is increasing from 4, 7, 13, 25.

35- 28 = 7 

48 - 35 = 13

73 - 48 = 25

Differences between these differences:

7 -4 = 3

13 - 7 = 6

25 - 13 = 12

Second differences are: 3, 6, 12. The second differences are doubling 

the next difference should be 12 + 12 = 24

The next difference in the original series will be 25 + 24 = 49 

the next term in the series, add the difference (49) to the last term (73)

73+ 49 = 122

Thus, correct option is (a)

The second differences are doubling 12+12 = 24

Add the difference (49) to the last term (73)

Thus, correct option is (a)​​