Question

5,3,2=7 11,7,7=5 2,7,?=3

Answer 1

Given:

Series - 5,3,2=7 11,7,7=5

To Find:

2,7,?=3

Solution:

Let the missing number be = x.

Let the difference between the first number and the second be = y

Thus, y = 5 - 3 = 2

Let the difference between the second number and the third be = z

Thus, z = 3 - 2 = 1

Now,

 5 × y - 3 × z

= 5 × 2 - 3 × 1 =

= 10 - 3

= 7

Similarly for z -

11 × y - 7 × z =

= 11 × 3 - 7 × 4

= 33 - 28

= 5

For the third series -

= 2 × y - 7 × z

= 2 × 5 - 7 × (2 - x) =

= 10 - 14 + 7x =

= -4 + 7x

We know that this is equal to 3.

Hence 3 = -4 + 7x.

on computing - -7x = - 4 - 3

= -7x = - 7

x = 1

Answer: The value of x is 1