Question

Complete the below series: 11, 20, 38, 74, _____.

Answer 1

Answer is 146

Explanation: the difference between the number doubles itself and adds up with the number to form the next number.

20–11= 9, so 9+9=18, now the next number is 20+18=38

38–20=18, so 18+18= 36, the next number is 38+36=74

Now the series becomes:

11, 20, 38, 74,..

Now as the difference doubles itself and adds up with the last formed number to give the next number, so next number which should be added to 74 will be 36+36= 72

So 74+72= 146

And finally 72+72=144, adding 144 to 146 gives you 290

The complete series is 11, 20, 38, 74, 146, 290