Answer:
13 years
Step-by-step explanation:
x: The number of years until Alex is 5 times older than Will.
Now Later
Alex: 72 72+x
Will: 4 4+x
72+x = 5(4+x) Alex's age (72) plus x is 5 times older than Will's age plus x
72+x = 20+5x Just solve the equation
52 = 4x
x = 13 (years)
Answer: It will take 13 years for Alex to be 5 times as old as will