## EXOEXOEXO one year ago a motor boat travelling at 18 miles per hour travelled the length of a lake in one-quarter of an hour less time than it took when travelling at 12 miles per hour. what was the length in miles of the lake?

1. kropot72

Let the length of the lake be d miles and let the time to travel d miles at 12 mph be t hours. Now we can form two equations: $\large t=\frac{d}{12}\ ...............(1)$ $\large t-\frac{1}{4}=\frac{d}{18}\ ...........(2)$ If we now plug the value of t from equation (1) into equation (2) we get $\large \frac{d}{12}-\frac{1}{4}=\frac{d}{18}\ ...........(3)$ Now you need to solve equation (3) to find the value of d.

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