Answer:
13 years
Step-by-step explanation:
Let the unknown number of years be n.
Then 72 + n = 5(4 + n)
Performing the indicated multiplication,
72 + n = 20 + 5n
Grouping like terms gives us:
52 = 4n, and so n = 13.
In 13 more years, Ishaan will be 5 times over than William.
