Question

In still water, a speed boat travels 5 times faster than the current of the river. If the speed boat can travel 48 miles upstream and 10 back in 5 hours, find the rate.

Answer 1

u = 5 c

t = time upstream
(5-t) = time downstream

(u-c)t = 48
(u+c)(5-t) = 10

4 c t = 48 so t = 12/c
6 c (5-t) = 10

6 c (5 - 12/c) = 10

30 c - 72 = 10

30 c = 82

c = 2.7333
u = 5 c = 13 2/3 miles/hour

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by the way t = 12/2.73333 = 4.4
hours so 5 - t = .6 hours
check
u+c = 16.4
u-c = 10.9
10.9 *4.4 = 48 close enough
16.4 * .6 = 10 close enough

Answer 2

Angles and dgrees