Question 50119: Two cars are leaving Phils house at precisely at 6:20pm. The first car driven by Phil is headed nother. The second car, driven by Roman, is headed south Phil, because he is nat a good citizen is going 20 MPH faster than Roman. If at 7:50 they are exactly 168 miles apart, how fast is each going?
Please help me. Not sure of the equation
Thank you!
Found 2 solutions by stanbon, lkwtcnj:
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Two cars are leaving Phils house at precisely at 6:20pm. The first car driven by Phil is headed nother. The second car, driven by Roman, is headed south Phil, because he is nat a good citizen is going 20 MPH faster than Roman. If at 7:50 they are exactly 168 miles apart, how fast is each going?
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Roman car DATA:
rate = x mph ; time= (3/2)hr.; distance= rt= (3/2)x miles
Phil car DATA:
rate = x+20 mph ; time = (3/2)hr.; distance = rt = (3/2)(x+20)
EQUATION:
distance + distance = 168 miles
(3/2)x+(3/2)(x+20)= 168
3x+30=168
3x=138
x=46 mph (Romans car rate)
x+20= 66 mph (Phil's car rate)
Cheers
Stan H.
Answer by lkwtcnj(8) (Show Source):
You can put this solution on YOUR website! To get the distance, you multiply speed by time. So if you let Roman's speed be x, then Phil's speed is x + 20. 1.5 hours has passed. Then Roman has gone 1.5x, and Phil has gone 1.5(x+20). Since they're going in opposite directions, the distance between them is just the sum of their individual distances:
1.5(x + 20) + 1.5x = 168
1.5x + (1.5 * 20) + 1.5x = 168
3x + 30 = 168
3x = 168 - 30
3x = 138
x = 138/3 = 46
Then Roman is going 46 mph, and Phil is going 46 + 20 = 66 mph. Hope that helps!
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