Question

9 11 20 31 _ 82. What is the missing number?

Answer 1

the answer is 51
because
9+11=20
11+20=31
So 20+31=51
and31+51=82

Answer 2

Answer:

51

Step-by-step explanation:

Given : 9  11    20    31    _    82.

To Find : The missing term

Solution:

9  11    20    31    _    82.

Each term in the series is the sum of the preceding two terms

$9+11=20$

$20+11=31$

$31+20=51$

$51+31=82$

So, the missing term is 51 i.e. $31+20=51$

Hence the missing term of the given series is 51