SOLUTION: A goods train travel at a constant speed covers 5 hrs, when an express train moving 20km/h faster than the goods train covers the same distance in 3 hrs. find the speed of two trai

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Question 830906: A goods train travel at a constant speed covers 5 hrs, when an express train moving 20km/h faster than the goods train covers the same distance in 3 hrs. find the speed of two trains
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
Basic fact: highlight_green%28R%2AT=D%29
Let r be the speed of the goods train.
Let d be the distance that both trains travel in their known times. This is the same for both trains, allowing the equation of one variable only, as stated below the data table.

_________________speed____________time________________distance
Goods_____________r________________5___________________d
Express__________r+20______________3___________________d

Goods train: r%2A5=d
Express train: %28r%2B20%29%2A3=d
-
highlight_green%28r%2A5=%28r%2B20%29%2A3%29
Solve this equation for r.