Below you will see a series of equations, where the operator is used differently. Find the usage of the operator in the first 3 equations and then find the missing number in the last equation.

If,

1 + 4 = 5

2 + 5 = 12

3 + 6 = 21

Then,

5 + 8 = ?

Have you find the answer?

Check bellow:

Answer: 45

Explanation:

So we have the following equations;

1 + 4 = 5

2 + 5 = 12

3 + 6 = 21

of the form;

a + b = c

So we can find the actual operations are as follows;

a x (b + 1) = c

So in the equations let’s see if this is followed;

1 + 4 = 5 :: 1 x (4 + 1) = 1 x 5 = 5

2 + 5 = 12 :: 2 x (5 + 1) = 2 x 6 = 12

3 + 6 = 21 :: 3 x (6 + 1) = 3 x 7 =21

Therefore, if we apply the same to the equation with the missing number we can find the result;

5 + 8 = ? :: 5 x (8 + 1) = 5 x 9 = 45

Hence,

Answer = 45.