SOLUTION: There is a one mile oval track. The car goes around the track the first time at 30 mph. How fast must he go on his second lap to bring his second lap average up to 60 mph?

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Question 167224: There is a one mile oval track. The car goes around the track the first time at 30 mph. How fast must he go on his second lap to bring his second lap average up to 60 mph?
Found 3 solutions by Alan3354, jojo14344, Mathtut:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
There is a one mile oval track. The car goes around the track the first time at 30 mph. How fast must he go on his second lap to bring his second lap average up to 60 mph?
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This is a "trick question."
Travelling a mile at 30 mph takes 2 minutes.
Travelling 2 miles at 60 mph also takes 2 minutes, so the time is up, the car cannot average 60 mph for the 2 laps.
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The wording is a bit odd, tho. It says "second lap average..." If only the 2nd lap is considered, he has to go 60 mph to "average" 60 mph, but that's not actually an average.

Answer by jojo14344(1513) About Me  (Show Source):
You can put this solution on YOUR website!

I guess the question asked,"How much the 2nd lap should be to have an average of 60mph?" Then by Averaging,
Ave=%28Lap%5B1%5D%2BLap%5B2%5D%29%2F2
60=%2830%2BLap%5B2%5D%29%2F2, cross multiply
60%2A2=30%2BLap%5B2%5D
120-30=Lap%5B2%5D
highlight%28Lap%5B2%5D=90mph%29 ---> to have an Average of 60mph in 2 Laps.
If the re-phrase question is what it is.
thank you,
Jojo

Answer by Mathtut(3670) About Me  (Show Source):
You can put this solution on YOUR website!
d=r*t 1st lap rate of car is r%5B1%5D=+30mph
d=r*t 2nd lap rate is unknownr%5B2%5D=+unknown
%28r%5B1%5D%2Br%5B2%5D%29%2F2=60mph or r%5B1%5D%2Br%5B2%5D=120 r%5B2%5D=120-r%5B1%5D
r%5B2%5D=120-30=90
car has to travel at 90mph on 2nd lap in order to avg 60mph for both laps.