Question

A car travelled the first third of a distance xmat a speed of 10km/h, the second third at a speed of 20km/h and the last third at a speed of 60km/h. determine the average speed of the car over the entire distance x?

Answer 1

write a time equation; time = dist/speed; assume the total dist = 3
 +  +  = 
multiply eq by 60a, cancel the denominators and you have
6a + 3a + a = 60(3)
10a = 180
a = 180/10
a = 18 km/hr is the average for the trip

Answer 2

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____Answer is in Attachment !!______

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Hope it helps...

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