Question 982598


On a particular day, the wind added 4 miles per hour to Jaime's rate when she was rowing with the wind and subtracted 4 miles per hour from her rate on her return trip. Jaime found that in the same amount of time she could row 34 miles with the wind, she could go only 18 miles against the wind. What is her normal rowing speed with no wind?   Please help!
<pre>Let rowing speed of boat with no wind, be S
Then rowing speed with wind = S + 4, and rowing speed against wind = S - 4
Time taken to row 34 miles, with wind: {{{34/(S + 4)}}}
Time taken to row 18 miles, against wind: {{{18/(S - 4)}}}
Since times are the same, we get: 
{{{34/(S + 4) = 18/(S - 4)}}}
34(S - 4) = 18(S + 4) ------- Cross-multiplying
34S - 136 = 18S + 72
34S - 18S = 72 + 136
16S = 208
S, or speed with no wind = {{{208/16}}}, or {{{highlight_green(13)}}} mph