Question

Jim is 3 times as old as his cousin Anthony the difference in their age is 18.How old is Jim?

Answer 1

Let's create expressions and equations to model this situation. Let Anthony's age be a.

"Jim is 3 times as old as his cousin, Anthony." Jim's age is 3a.
"The difference in their age is 18." 3a - a = 18

How old is Jim?

Let's solve the above equation for a to first find Anthony's age.

    3a - a = 18
    2a = 18
    a = 9

Remember, Jim's age is represented by the expression 3a. Substitute Anthony's age, 9, into the expression to find Jim's age.

    3a
    3(9)
    27

Answer:
Jim is 27 years old.