SOLUTION: A bus is 13 kilometers from town, going away at 80km/h. At the same moment a car leaves town going the same direction as the bus, at the same speed. x = number of hours the c

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: A bus is 13 kilometers from town, going away at 80km/h. At the same moment a car leaves town going the same direction as the bus, at the same speed. x = number of hours the c      Log On

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Question 637973: A bus is 13 kilometers from town, going away at 80km/h. At the same moment a car leaves town going the same direction as the bus, at the same speed.
x = number of hours the car and bus have been going
80x = car's distance from town
13 + 80x = bus's distance from town
After how long will the bus's distance be twice the car's distance?
I already know that it will happen when the bus is 26 km from town, and the car is 13 km from town, meaning they've each traveled 13km. At 80km/h this means it will happen at 13/80 of an hour, or 9.75 minutes. But I can't figure out how to write an algebraic equation showing this. Here is what I tried, and I get a negative number:
80x = 2 * 80x + 13
80x - 13 = 160x
-13 = 80x
-13/80 = 80x/80

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
given:
+d%5Bc%5D+=+80x+ km
+d%5Bb%5D+=+13+%2B+80x+ km
+d%5Bb%5D+=+2d%5Bc%5D+ km
+13+%2B+80x+=+2%2A80x+ *
+13+%2B+80x+=+160x+
+80x+=+13+
+x+=+13%2F80+ hrs
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* you just wrote this backwards