SOLUTION: Increasing the average speed of the Pickerinton Express Bus by 13 km/h resulted in the 260 km trip taking an hour less than before. What was the original average speed of the bus?

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Question 26982: Increasing the average speed of the Pickerinton Express Bus by 13 km/h resulted in the 260 km trip taking an hour less than before. What was the original average speed of the bus?
Answer by Paul(988) About Me  (Show Source):
You can put this solution on YOUR website!
260%2Fx-260%2F%28x%2B13%29=1
260[(x)-(x+13)=(x)(x+10)
260%2813%29=x%5E2%2B13x
x%5E2%2B13x-3380=0
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
a=1, b=13, c=-3380
x=%28-13%2B-sqrt%28%2813%29%5E2-4%281%29%28-3380%29%29%29%2F%282%2A1%29
x=%28-13%2B-sqrt%28169%2B13520%29%29%2F%282%29
x=%28-13%2B-sqrt%2813689%29%29%2F%282%29
x=%28-13-117%29%2F%282%29 or x=%28-13%2B117%29%2F%282%29
x=-65 or x=52

Remove the negative x=52.
Hence, the speed of the bus is 52km/h.
Paul.