On a trip, the fare was 50¢ for each adult and 25¢ for each child. if 30 passengers paid $12.25, how many adults and children went?
is this the right way to set up the equation?
50x + 25(30 - x) = 1225

Fare for each adult = 0.50 dollars
Fare for each child = 0.25 dollars
Total number of passengers = 30
Total amount paid for the trip = 30 dollars
Lat us assume the number of adults = x
Then
The number of children = 30 - x
So
0.50x + 0.25(30 - x) = 12.25
50x + 25(30 - x) = 1225
This is the right way of setting up the equation and you have done it correctly. 

It will be a whole number.

8,400-6,400=xx/6,400anyways the percent increase is 31.25% or 0.3125 you can round if you can