Question 1171113
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The work you show in your post indicates you are going to use the distance of 64 miles, the speed of the boat in still water, and an unknown for the speed of the current, to find expressions for the times traveled upstream and downstream; then you will be able to answer the problem by solving the equation that says the upstream time is three times the downstream time.<br>
That is a perfectly good method for solving the problem; and the other tutor has provided a solution using that method.<br>
The work required to reach the answer is far less if a different approach is used.<br>
The distances are the same, so if the upstream times is 3 times the downstream time, then the downstream speed is 3 times the upstream speed.<br>
Let x be the unknown speed of the current; then<br>
{{{8+x = 3(8-x)}}}
{{{8+x = 24-3x}}}
{{{4x = 16}}}
{{{x = 4}}}<br>
ANSWER: The speed of the current is 4 km/h.<br>