SOLUTION: David participates in a bicycle race in which a rider starts every 5 minutes. David's average is 33 km/hr. After 28 minutes, he is overtaken by a rider who started 2 persons after

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Question 635338: David participates in a bicycle race in which a rider starts every 5 minutes. David's average is 33 km/hr. After 28 minutes, he is overtaken by a rider who started 2 persons after him. What is the rate of the other cyclist in km/hr?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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David participates in a bicycle race in which a rider starts every 5 minutes.
David's average is 33 km/hr.
After 28 minutes, he is overtaken by a rider who started 2 persons after him. What is the rate of the other cyclist in km/hr?
:
Let s = speed of the 2nd cyclist
:
From the information given, the 2nd rider started 15 min behind David
:
Change 28 min to hrs: 28%2F60 hrs, David's travel time
Change (28-15) = 13%2F60 hrs, 2nd rider's travel time
:
When this happens, they will have traveled the same distance.
Write a distance equation; dist = speed * time
:
13%2F60s = 28%2F60(33)
multiply both sides by 60
13s = 28(33)
13s = 924
s = 924/13
s = 71.1 km/hr, speed of the 2nd rider
:
:
Confirm this by finding the distance of each
13%2F60*71.1 = 15.4 km
28%2F60*33 = 15.4 km