SOLUTION: A model train traveling a 210 meter circle track clockwise at 20 meters per minute. Another model train traveling a 210 meter circle track counterclockwise at 15 meters per minute.

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Question 1054968: A model train traveling a 210 meter circle track clockwise at 20 meters per minute. Another model train traveling a 210 meter circle track counterclockwise at 15 meters per minute. How long will it take the trains to pass eachother
Found 2 solutions by addingup, Theo:
Answer by addingup(3677) About Me  (Show Source):
You can put this solution on YOUR website!
210/35 = 6 minutes

Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
the first train travels at 20 meters per minute.
the second train travels at 15 meters per minute.

let x equal the number of meters that the first train travels.
let 210 - x equal the number of meters that the second train travels.

they will meet at some point equal to or before one of the trains has traveled 210 meters.

for the first train, that will be when it has traveled x meters.
for the second train, that will be when it has traveled 210 - x meters.

this will happen when both trains have traveled for the same amount of time.

the general formula is rate * time = distance.

for the first train, this formula becomes 20 * T = x

for the second train, this formula becomes 15 * T = 210 - x

since x = 20 * T in the first equation, replace x with 20 * T in the second equation to get:

15 * T = 210 - 20 * T

add 20 * T to both sides of this equation to get 35 * T = 210.

divide both sides of this equation by 35 to get T = 6.

the trains will meet in 6 minutes.

the first train will have traveled 20 * 6 = 120 meters.

the second train will have traveled 15 * 6 = 90 meters.

the total distance traveled by both trains is equal to 120 + 90 = 210 meters.