Math
posted by Stella .
Hello, I have trouble doing this problem:
Sarah can bicycle a loop around the north part of Lake Washington in 2 hours and 40 minutes. If she could increase her average speed by 1km/hr, it would reduce her time around the loop by 6 minutes. How many kilometers long is the loop?
So this is what I attempted to do:
I change the 2hours 40 min to 160 mins
then i tried changing it to hours which was 2.6666667
and i tried to plug it in
d=r*t
but then i got confused..please help me =)

Math 
drwls
Let L be the loop distance. Let V be her speed when it takes 2.6667 hours.
You have two unknowns and must combine two equations to get an answer.
At speed V + 1 , she takes 2 hours 34 minutes = 2.5667 hours
At speed V, she takes 2.6667 hours
D = V * 2.6667 = (V+1)* 2.5667
(V+1)/V = 2.6667/2.5667 = 1.03896
V + 1 = 1.03896 V
0.03896 V = 1
V = 25.67 km/h
D = 25.67 * 2.6667 = 68.4 km
Respond to this Question
Similar Questions

Physics
A bicyclist makes a trip that consists of three parts, each in the same direction (due north) along a straight road. During the first part, she rides for 22 minutes at an average speed of 6.60 m/s. During the second part, she rides … 
Physics
A bicyclist makes a trip that consists of three parts, each in the same direction (due north) along a straight road. During the first part, she rides for 22 minutes at an average speed of 6.60 m/s. During the second part, she rides … 
Physics
A bicyclist makes a trip that consists of three parts, each in the same direction (due north) along a straight road. During the first part, she rides for 22 minutes at an average speed of 6.60 m/s. During the second part, she rides … 
Ash
A bicyclist makes a trip that consists of three parts, each in the same direction (due north) along a straight road. During the first part, she rides for 22 minutes at an average speed of 6.80 m/s. During the second part, she rides … 
Phyiscs
A bicyclist makes a trip that consists of three parts, each in the same direction (due north) along a straight road. During the first part, she rides for 22 minutes at an average speed of 6.80 m/s. During the second part, she rides … 
physics
A senior citizen walks 0.36km in 11min , going around a shopping mall.What is her average speed in meters per second? 
Algebra1
1. A bicycle racer covers a 75 mile training route to prepare for an upcoming race. If the racer could increase his speed by 5 mph, he would complete the same course in 3/4 of the time. Find his average rate of speed. 2. Nina drove … 
physics
A senior citizen walks 275 m in 25 min going around a shopping mall. If she wants to increase her average speed by 25 % in walking a second lap, what would her travel time in minutes have to be? 
Math
Several cows from a Caribou Herd took 4 days longer to travel 70km to Forde Lake, than it took them to travel 60km north beyond forde lake.They averaged 5km/h less before Forde lake because the foraging was better. What was their average … 
Physics
A bicyclist makes a trip that consists of three parts, each in the same direction (due north) along a straight road. During the first part, she rides for 23.7 minutes at an average speed of 6.31 m/s. During the second part, she rides …