<PRE><B>Question 509029</B>
Randy can row upstream at 4 mph and downstream at 10mph.
 If the round trip from Randys home upstream to Sandys home (and back) takes 9.5 hours then about how far apart are their homes?
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Let d = the one-way distance
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Write a time equation; time = dist/speed
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up time + down time = 9.5 hrs
{{{d/4}}} + {{{d/10}}} = 9.5
multiply by 20 to clear the denominators
5d + 2d = 20*9.5
7d = 190
d = 27.14 ~ 27 miles apart
:
:
Check this solution find the time for each way
27/4 = 6.75
27/10= 2.70
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total: 9.45 ~ 9.5
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