We inspect each of the choices and determine which among them is the best answer by multiplying the given time frames to the speed given.
(a) (3 2/5 miles/day) x (4 days) = 13.6 miles (wrong)
(b) (3 2/5 miles/day) x (7 days) = 23 4/5 miles (correct)
(c) (3 2/5 miles/day) x (10 days) = 34 miles (correct)
(D) (3 2/5 miles/day) x (31 days) = 105.4 miles (wrong)
Thus, the answers are B and C.
