Question

13,30,?,148,273
Find the missing no. In the series

Answer 1

Answer:

75

Explanation:

Let the missing number be x.

13               30             x            148 .......

      17              x-30         148-x   --- 1st level difference

Let y be the common addition factor for 2nd level difference.

17 + y = x - 30  .... (1)

x-30 + y = 148 - x .... (2)

Solving (1) and (2) we get, x-y = 47; 2x + y = 178

3x = 225

Therefore, x = 75

So the missing number is 75.