SOLUTION: A train leaves New York at 2:00 PM. A second train leaves the same city in the same direction at 7:00 PM. The second train travels 150 mph faster than the first. If the second trai

Algebra ->  Length-and-distance -> SOLUTION: A train leaves New York at 2:00 PM. A second train leaves the same city in the same direction at 7:00 PM. The second train travels 150 mph faster than the first. If the second trai      Log On


   



Question 1049669: A train leaves New York at 2:00 PM. A second train leaves the same city in the same direction at 7:00 PM. The second train travels 150 mph faster than the first. If the second train overtakes the first at 9:00 PM, what is the speed of each of the two trains?
Found 2 solutions by advanced_Learner, josgarithmetic:
Answer by advanced_Learner(501) About Me  (Show Source):
You can put this solution on YOUR website!
slower train speed r
time 7
distance 7r

fast train speed r+150
time 2
distance (r+150)*(2)

at t=7 distance are equal
(r+150)(2)=7r
2r+300=7r
r=60 mph
faster train speed is 210
check
first train leaves at 2,
after one hour 60 miles
after 2 hour 120
after 3 hour 180
after 4 hour 240
after 5 hour 300
after 6 hour 360
after 7 hour 420 miles this is 9pm
second train leaves at 7
after one hour 210 miles
after 2 hour 420 miles this is 9 pm
after 3 hour 630 miles

Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Look at time quantities first, and no adjustments for time points later needed. Second train begins travel five hours after the New York departure train. The overtake time is 9-2=7 hours for the New York first departure train, and 9-7=2 hours for the second train.
Which Depart Time    SPEED         TIME        DISTANCE
2PM TRAIN              r            7            d
7PM TRAIN             r+150         2            d


Basic constant travel rate rule is RT=D.

system%28%28r%29%287%29=d%2C%28r%2B150%29%282%29=d%29

highlight%287r=2%28r%2B150%29%29