Question

The sum of three numbers is 72

The second number is 7 times the first.
The third number is 18 less than the second
What is the first number?​

Answer 1

Let the first number be x, second number be 7x and the third number be 7x-18. Then,

Sum of the numbers=72

or, x+(7x) +(7x-18)=72

or, 15x=90

or, x=6

So, the first number is 6.