Question

find the missing no.-3,8,24,48,?,168

Answer 1

3, 8, 24, 48,  ...,  168

2²-1,  3²-2,  5²-1 ,  7²-1, .. ,  13² -1

prime numbers... 2,3,5, 7,  11,  13..
so missing number is  11²-1 = 120

Answer 2

If you add 1 to each number, you can see that they are square of numbers
3+1 = 4 = 2^2
8+1 = 9 = 3^2
24+1 = 25 = 5^2
48+1 = 49 = 7^2
168+1 = 169 = 13^2
All are prime squares.
The missing prime is 11
So answer is 11^2 - 1 = 121-1=120