Question 1182752
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The ratio of the speeds of the two boats is 20:5 = 4:1, so the ratio of distances traveled is 4:1.<br>
If your mental arithmetic is good, you can solve that mentally -- the small boat travels 2 of the 10 miles and the Coast Guard boat travels 8.<br>
Or if you need to use formal algebra, using the ratio 4:1 of the distances traveled by the two boats, the small boat travels x miles and the Coast Guard boat travels 4x miles, and the total distance traveled is 10 miles:
x+4x=10
5x=10
x=2
4x=8<br>
The required time can be determined using the distance and speed of either boat: 2 miles at 5 knots for the small boat or 8 miles at 20 knots for the Coast Guard boat.<br>
Of course you need to deal with the conversion between knots and miles per hour; that part I leave to you.<br>