Question

a boat is taking a cruise to a remote island 800 miles away. The trip downstream with current is 8 mile per hour. the return trip upstream against current is 10 hours. find the speed of the boat in still water and speed of current

Answer 1

v + c = 8

v - c on the way up
(v-c)10 = 800 so v - c = 80
NO WAY typo

Answer 2

Given:
d = 800 Miles.
T1 = 8 hours, downstream.
T2 = 10 hours, upstream.

(Vb+Vc)8 = 800.
Eq1: Vb + Vc = 100.

(Vb-Vc)10 = 800.
Eq2: Vb-Vc = 80.

Add Eq1 and Eq2:
Vb + Vc = 100.
Vb - Vc = 80.
2Vb = 180.
Vb = 90 mi/h.

In Eq1, replace Vb with 90:
90 + Vc = 100.
Vc = 10 mi/h.