Answer:
(a) He solved <em>m</em>/5 problems everyday.
(b) He solved 75 problems during his vacation.
(c) If he solved 15 problems per day, then 75 problems were assigned for homework. Otherwise, he had <em>m</em> problems assigned for homework.
Explanation:
(a) <em>m</em> math problems were assigned, and he completed them in 5 days. So divide the number of problems with the number of days.
(b) If he was solving 15 problems per day, then 15×5 = 75 problems.
(c) 75 problems were assigned for homework if he was doing 15 problems a day. Otherwise, he was assigned <em>m</em> problems for homework.