Answer:
t = 100 minutes, or 1 hr, 40 minutes
Explanation:
5/15 of 1 hour is the same as 5/15 of 60 minutes, which is 20 minutes
you can set up a proportion of hw completed / minutes = hw completed / min:
(1/5 ÷ 20) = (1 ÷ t) we use '1' to indicate all homework (or 100% of hw) and 't' to indicate time required
cross-multiply to get:
20 = 5/t
t = 100 minutes, or 1 hr, 40 minutes