Question

PLS HELP!!! there were 90 runners to start a race. In the first half of the race, 1/3 of them dropped out. In the second half of the race, 2/3 of the remaining runners dropped out.

Answer 1

There were 90 runners to start a race.

If 1/3 dropped out, that means only 2/3 of them are left, so we have:

Number remaining after the first round of dropout =
`(2)/(3) *90 = (180)/(3) =60`

If 2/3 dropped out in the second half, only 1/3 of them are left, so we have

Number remaining after the second round of dropout =
`(1)/(3) *60 = 20`

Thus there are 20 runners remaining at the end.