Question

what is the missing number in the series 7,x,21,31,43

Answer 1

the difference between 43&31 is 12, 31&21 is 10,so 21&x is some 8 so difference between 7&x is 6 hence the number must be 13

Answer 2

The value of x is 13.

Step-by-step explanation:

Given series= 7,x ,21,31,43

To find= the value of x

Solution:

We will start by finding the difference between the consecutive numbers:

difference between 21 and 31= 31-21= 10

Difference between 31 and 43= 43-31= 12

We can see that the series follow a pattern of (d+2) difference.

If the difference between 21 and 31 is 10, then the difference between x and 21 should be 8.

x= 21-d

x= 21-8= 13

Result:

Thus the value of x is 13.

(#SPJ3)