Question

Rachel finished 3/4 of the race in 6 hours. How much time did it take her to finish the entire race?

Answer 1

8 Hours

Explanation:

Given: 3/4 part of race completed in 6 hours.

Formula for finding speed is,

Speed=
`(distance)/(time)`

Now, lets find out the speed at which
`(3)/(4)` of the race completed.

Speed=
`((3)/(4) )/(6) = (1)/(8)`

∴ Speed was
`(1)/(8)` to complete
`(3)/(4)` of the race.

Lets find out the remaining part of race:

`1 - (3)/(4)` =
`(1)/(4)`

∴
`(1)/(4)` part of the race is yet to be completed.

Now, time taken to finish
`(1)/(4)` part of race at the same speed of
`(1)/(8)`.

Formula for finding time is,

Time=
`(distance)/(speed)`

Time (
`T_2`)=
`((1)/(4) )/((1)/(8) )` = 2
`\ hours`

∴ Time taken to finish remaining
`(1)/(4)` part of race is 2
`\ hours`

Now, to find out total time taken to finish entire race is:

Total time=
`T_1 + T_2`

Total time =
`6+2 = 8 \ hours`

∴ Total time taken to finish entire race is 8
`\ hours`