The Answer is 2/3
Steps: 1/4(1-(2/3^2+1/3)
In the question, it is already given that the total number of runners in the race is 60 and out of them 1/3 dropped out in the first half. In the second half 1/4 of the remaining runners dropped out.
Now
Total number of runners in the race = 60
Number of runners that dropped out in the first half = 1/3 * 60
= 20
Number of runners remaining = 60 - 20
= 40
Number of runners dropping out in the second half = 40 * 1/4
= 10
Then the number of runners that finished the race = 40 - 10
= 30
Then 30 runners completed the race.
I need to know how many miles the race is
This question is obviosly missing an ending but, I bet you will have to divide.