Question 255290
.Troy and Phil agree to meet at the movies.Phil drives 24 miles while troy rides his bike the 5 miles from his house at a speed of 15 miles per hour.
If troy left 15 minutes later than Phil and they arrived at the theater at the same time, how fast did phil drive?
:
Let s = Phil's speed
Change 15 min to 1/4 hr
:
Write a time equation; Time = dist/speed
:
P's time = T's time + 15 min
{{{24/s}}} = {{{5/15}}} + {{{1/4}}}
Multiply equation by 60s, results
60(24) = 4s(5) + 15s
:
1440 = 20s + 15s
:
1440 = 35s
s = {{{1440/35}}}
s = 41.14 mph is Phil's speed
:
:
Check solution by finding the travel time of each
24/41.14 = .583 hr
15/5 = .333 hr
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difference .25 hr (15 min)