SOLUTION: Train A has a speed 20 miles per hour greater than that of train B. If train A travels 210 miles in the same times train B travels 170 miles, what are the speeds of the two trains?

Question 890789: Train A has a speed 20 miles per hour greater than that of train B. If train A travels 210 miles in the same times train B travels 170 miles, what are the speeds of the two trains?
Found 2 solutions by JulietG, ptaylor:
Answer by JulietG(1812) (Show Source): You can put this solution on YOUR website!
The difference in distance traveled is 210-170, or 40 miles
The difference in speed is 20 mph (given).
40 miles / 20 mph = 2 hours.
Train A traveled 210 miles in 2 hours for a speed of 105 mph
Train B traveled 170 miles in 2 hours for a speed of 85 mph
Answer by ptaylor(2198) (Show Source): You can put this solution on YOUR website!
Distance(d) equals Rate(r)times Time(t)or d=rt;r=d/t and t=d/r
Let r=train B's speed
Then r+20=train A's speed
Time required for train A to travel 210 mi=210/(r+20)
Time required for train B to travel 170 mi=170/r
Now we are told that these times are equal, so:
210/(r+20)=170/r divide each term by 10 to simplify
21/(r+20)=17/r multiply each term by r(r+20)
21r=17(r+20) expand
21r=17r+340 subtract 17r from each side
4r=340
r=85 mph---Train B's speed
r+20=85+20=105 mph---train A's speed
CK
210/105 =170/85
2=2
Hope this helps-----ptaylor
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