Question 1186506
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The speed of the wind increased from 15 mph to 15 + 30 = 45 mph.

The area of the sail did not change.


With the speed of the wind increased thrice, the new force is 3^2 = 9 times as large as 45 pounds, i.e. 


     9 * 15 = 135  pounds.    <U>ANSWER</U>
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Solved and answered.