Question 676400
A sailboat departed from an island and traveled north for 2 hours, then east
 for 1 and 1/2 hours all at the same speed. 
At the end of the trip the boat was 20 miles from where it started.
 At what speed did the boat travel?
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Let s = speed of the boat
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This is a pythag problem: a^2 + b^2 = c^2, where
a = the distance travel north after 2 hrs
b = the distance travel east after 1.5 hrs
c = 20 mi
: 
(2s)^2 + (1.5s)^2 = 20^2
4s^2 + 2.25s^2 = 400
6.25s^2 = 400
s^2 = {{{400/6.25}}}
s^2 = 64
s = {{{sqrt(64)}}}
s = 8 mph is the boat speed
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