SOLUTION: A cyclist has to make a 30km trip. She leaves 3 minutes late, but travels 1km/hr faster than she planned, and finally arrives on time. At what speed did the cyclist travel?
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Question 803121: A cyclist has to make a 30km trip. She leaves 3 minutes late, but travels 1km/hr faster than she planned, and finally arrives on time. At what speed did the cyclist travel?
I am trying to solve it as follow:
30 km = rt
30 km = (r+1)(t-3)
Does it make sense?
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
Distance = 30 km
let the speed she has to travel be x to reach on time
she travels 1km faster => x+1 km/h
The time difference with both speeds = 3 minutes = 3/60 = 1/20 hours
30/x -30/(x+1) = 1/20
30(x+1)-30x= x(x+1)/20
30x+30-30x=(x^2+x)/20
30=(x^2+x)/20
30*20 = x^2+x
x^2+x-600=0
x^2+25x-24x-600=0
x(x+25)-24(x+25)=0
(x+25)(x-24)=0
x=-25 OR 24
ignore negative
speed = 24 km/h
increased speed = 24 +1 = 25 km/h
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