Two trains leave a station at the same time, heading in opposite directions. One train is traveling at 80 km-h, the other at 90 km-h. How long will it be for the trains to be 425 km Apart?
distance = rate x time
d = rt
One train
rate = 80
time = t {they left at the same time}
d = 80t {distance = rate x time}
Other train
rate = 90
time = t {they left at the same time}
d = 90t {distance = rate x time}
To find out when they are 425 apart, add the distances and set equal to 425
80t + 90t = 425 {added distances and set equal to 425}
170t = 425 {combined like terms}
t = 2.5 {divided both sides by 170}
In 2.5 hours, they will be 425 km apart
© Algebra House
