Question

The sum of three consecutive odd natural numbers is 69 . Find the prime number out of these numbers

Answer 1

Let the numbers be a, a +2 and a + 4

A. T. Q

a + a + 2 + a + 4 = 69

=> 3a + 6 = 69

=> 3a = 63

=> a = 21

First number = 21

Second number = 23

Third number = 25

Prime number is 23.

Answer 2

Let number are ( 2x + 1 ), ( 2x + 3 ), ( 2x + 5 )




$\textcolor{red}{their \: \: sum \: \: = 69}$

=> 2x + 1 + 2x + 3 + 2x + 5 = 69


=> 6x + 9 = 69

=> 6x = 60

=> x = 10



Numbers are :-

( 2x + 1 ) = [ 2(10) + 1 ] = 21

( 2x + 3 ) = [2(10) + 3 ] = 23

( 2x + 5 ) = [ 2(10) + 5 ] = 25




$\fcolorbox{blue}{yellow}{ \: \: \: prime \: number \: = 23 \: \: \: }$