Answer:
48
Step-by-step explanation:
Lets assume that the third runner up eats x hot dogs.
The total time for the contest is 15x seconds.
Given is that the winner ate (x+24) hot dogs
The winner's rate of eating is 1 hot dog per 7.5 seconds.
And we know the rate = total time/number of hot dog eaten
We get;

solving we get x= 24
therefore the winner ate 24+24= 48