A cyclist bikes x distance at 10 miles per hour and returns over the same path at 8 miles pr hour.?

Question

What is the cyclist's average rate for the round trip in miles per hour?
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Please explain how u got ur answers.

Answer 1

1 / ((1/10 + 1/8) / 2) = 8 8/9.

Answer 2

In word problems that include miles per hour you have to reduce the number to a fraction. 10 mph becomes 1/10 8 mph becomes 1/8 2 = one hour each way. Your formula: 1/10 + 1/8 = 2. Now you have to make the denominators the same number. 10 and 8 have to be raised to 40 so they are the same by multiplying the 1/10 by 4/4 and the 1/8 by 5/5 1/10 * 4/4 = 4/40 and 1/8 * 5/5 = 5/40 Now rewrite equation. 4/40 + 5/40 = 2 9/40 = 2 .................. now you have 9/40 = 2/1 cross multiply 9*1 and 40 * 2 and you get: 80/9......80 ÷ 9 = 8.9 rounded off.

Answer 3

10 plus 8 = 18 divided by 2 = 9 miles per hour

Answer 4

total distance = 2x
total time = (x/10+x/8)

average speed = total distance/time
= 2/(1/10+1/8)
= 2*40/(4+5)
= 80/9
= 8.88888888 mph

Answer 5

Total distance: 2x
Total time: x/10 + x/8 = 4x/40 + 5x/40 = 9x/40
Distance = rate * time, so:
2x / (9x/40) = 2x * 40/9x = 80/9 = 8 8/9 mph.

Answer 6

Funda1: Avg speed= total distance/total time

Here total distance =x for going + x for coming=2x
Total time= time to go + time to return

Now time to go = distance to go/speed to go=x/10
Time to return=x/8
therefore avg speed=2x/[x/10+x/8]

as you simplify the x gets cancelled
so 2x/[18x/80]=2x 80/18x =80/9 miles per hour

Answer 7

(10 + 8)/2 = 18/2 = 9mph

Answer 8

if your cyclist friend returned back to the same location, the total change in location would be zero. zero divided by anything is zero. so the average speed was zero.