Question

find three consecutive natural number such that the sum of the first and the second is 15 more than third

Answer 1

lets consecutive odd number x,x+1,x+2 
so 
atq
x+x+1=x+2+15
x=16

Answer 2

Let the 1st number be x

As the numbers are consecutive,

2nd number = x + 1

3rd number = x + 2

Given,

They are in such a way that the sum of the first and the second is 15 more than third

so,
by balancing the equation, we have

x + x + 1 = x + 2 + 15

2x + 1 = x + 17

2x - x = 17 - 1

x = 16

So,

1st number = x = 16

2nd number = x + 1 = 16 + 1 = 17

3rd number = x + 2 = 16 + 2 = 18

So,

the numbers are 16, 17 and 18.