Question 403749
From a point on a river, two boats are driven in opposite directions, one at 8 mph and the other at 11mph.  In how many hours will they be 57 miles apart?


{{{Distance/Speed}}} = Time


Distance = 57 miles. In this case, we can easily add the speeds to get a total speed of 19 (8 + 11) mph


We therefore have: {{{57/19}}} = {{{highlight_green(3)}}} hours

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We also could have solved by adding the distances traveled by both vehicles and solving


In other words, Distance traveled by slower vehicle + distance taveled by faster vehicle = 57 miles


Let the time it takes the vehicles to cover their respective distances be T


Distance traveled by slower vehicle = 8T


Distance taveled by faster vehicle = 11T


As mentioned before, distance traveled by slower vehicle + distance taveled by faster vehicle = 57 miles


8T + 11T = 57


19T = 57


T, or time taken = {{{57/19}}} = {{{highlight_green(3)}}} hours.