Question

Question 85

Solve the following:

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

Answer 1

Let the three consecutive odd natural numbers be x, (x+2) and (x+4).
According to the question,
x+(x+2)+(x+4)=69
$\Rightarrow 3x+6=69\Rightarrow 3x=69-6\Rightarrow 3x=63\therefore x=63\times \frac{1}{3}=21$
Thus, the three consecutive odd natural numbers are 21, (21+2) and (21+4), i.e. 21, 23, and 25. Out of these, Only 23 is the prime number.