What is it asking it is not showing
The average rate is 5 mps because 80 seconds times 5 equals 400 meters
Let
x-----------> the number of kids
y----------> the number of adults
we know that
2.5x+6y=$7150---------> equation 1
x=2y-------------> equation 2
substitute 2 in 1
2.5*[2y]+6y=7150-----> 5y+6y=7150----> 11y=7150-----> y=650
x=2y----> x=2*650----> 1300
the answer is
the number of kids is 1300
