Question

Sum of two number is 72. One number is 30 more than the other. Let x be the smallr number and y be the bigger number. Write an Equation.

Answer 1

x+(x+30)=72

Explanation:

if x is the smaller number and y is the bigger number, then according to the condition (one number is 30 more than the other) y=x+30.

It the sum of the two numbers is 72, then x+y=72.

After substitution y=x+30:

x+(x+30)=72; - the required equation.

⇔ 2x=42; ⇒ x=21 (it is the smaller number)

y=51 (it is the bigger number).