Question

There were 45 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, 2/5 of the remaining runners dropped out. How many runners finished the race?

Answer 1

a 1/3 or 45 is 15 so there is 30 runners left. 2/5 of 30 is 12 so in the end 18 runners finished.

answer: 18

Answer 2

18

Explanation:

Given: There were
`45` 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)/(5)` of the remaining runners dropped out.

To Find: How many runners finished the race.

Solution:

Total number of runners
`=45`

Number of runners dropped out in first half of the race
`=(1)/(3)\text{of total}`

`(1)/(3)*45`

`15`

Number of runners remaining after first half
`=\text{Total runners before first half}-\text{number of runners dropped out}`

`45-15=30`

Number of runners dropped out in second half
`=(2)/(5)\text{of remaining after first half}`

`(2)/(5)*30`

`12`

Number of runners who finished the race
`=\text{runners remaining after first half}-\text{runners dropped in second half}`

`30-12=18`

Therefore
`18` runners finished the race.