SOLUTION: Justin can run 10 km in the same amount of time that Leo can run 12 km. if Leo can run 1 kph faster than Justin, how fast can Leo run?

Question 1179934: Justin can run 10 km in the same amount of time that Leo can run 12 km. if Leo can run 1 kph faster than Justin, how fast can Leo run?
Found 2 solutions by mananth, greenestamps:
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!

Justin can run 10 km in the same amount of time that Leo can run 12 km. if Leo can run 1 kph faster than Justin, how fast can Leo run?
let Justin's speed be x km/h
Leo's speed = x+1 km/h
Justin's time = 10/x
Leo's time = 12/(x+1)
Both times are equal
10/x = 12/(x+1)
10(x+1) =12x
10x +10 =12x
2x=10
x= 5 Justin's speed
Leo's speed = 6 km/h
Answer by greenestamps(13200) (Show Source): You can put this solution on YOUR website!

The response from the other tutors solve the problem by using the "times are the same" equation:
Justin's time = 10km/x mph
Leo's time =12km/(x+1)mph

That leads to a relatively easy solution using basic algebra.

Setting up the problem using a different proportion makes solving the problem easier.

Since the times are the same, the ratio of distances is equal to the ratio of speeds:

Simplify the numerical fraction on the left:

That equation COULD be solved using formal algebra; but it can also be solved by inspection: x=5 makes the fraction on the right 6/5, which is the same as the fraction on the left.

ANSWER: Leo's speed is x+1=6 mph

RELATED QUESTIONS
Justin can run 10 km in the same amount of time that Leo can run 12 km. If Leo can run 1... (answered by ankor@dixie-net.com,MathTherapy)
Justin can run 10 kilometers in the same amount of time that Leo can run 12 kilometers.... (answered by ikleyn,greenestamps,josgarithmetic)
Justin can run 10 km in the same time that enzo can run in 12 km. If enzo can run 1 kph... (answered by ikleyn)
Jane can run 5 kilometers in the same amount of time that Larry can run 6 kilometers, If... (answered by jorel1380,MathTherapy)
Qui-Gon Jinn can run 1 km/hr faster than Mace Windu. Qui-Gon can run 20 km in the same... (answered by ikleyn,greenestamps)
I can bike 4 miles in the same amount of time as it takes my friend to run 3 miles. If I... (answered by lwsshak3)
A man can ride his bike 18 miles in the same time it takes him to run 6 miles. He can... (answered by TimothyLamb,MathTherapy)
Bugs bunny can run nine miles in the same time Elmer Fud can run one mile.If Bugs Bunny... (answered by ikleyn)
A jogger can bike 30 miles in the same time as he can run 10 miles. If he can bike 10... (answered by ankor@dixie-net.com)