TOPIC :-

Playing with Numbers

Given :-

The sum of five consecutive numbers is 20.

To Find :-

Sum of the first THREE consecutive numbers.

Solution :-

Let first NUMBER be 'X'.

Then consecutive number after 'x' will be 'x + 1'.

Similarly,

Consecutive number after 'x + 1' will be 'x + 2'.

Consecutive number after 'x + 2' will be 'x + 3'.

Consecutive number after 'x + 3' will be 'x + 4'.

So,

5 Consecutive Numbers are,

x, (x + 1), (x + 2), (x + 3) and (x + 4)

It is given that sum of these numbers is 20.

x + (x + 1) + (x + 2) + (x + 3) + (x + 4) = 20

x + x + x + x + x + 1 + 2 + 3 + 4 = 20

5x + 10 = 20

5x = 20 - 10

5x = 10

x = 10/5 = 2

So, first number among those 5 numbers is 2.

Other Consecutive numbers are :

x + 1 = 2 + 1 = 3

x + 2 = 2 + 2 = 4

x + 3 = 2 + 3 = 5

x + 4 = 2 + 4 = 6

So, 5 consecutive numbers are 2, 3, 4, 5 and 6.

Calculating sum of first three consecutive numbers :-

First three consecutive numbers are 2, 3 and 4.

Sum of 2, 3 and 4 is,

2 + 3 + 4

9

Answer :-

So, sum of first three consecutive numbers is 9.