Answer:
100
Explanation:
Given a candy machine with 200 gumballs dispensed 1 at a time, and another with 900 chocolates dispensed 8 at a time, you want to know how many dispenses from each will result in equal counts left in the machines.
Gumballs
The number of remaining gumballs after d dispenses is ...
g = 200 -d
Chocolates
The number of remaining chocolates after d dispenses is ...
c = 900 -8d
Equal numbers
The number remaining in each machine will be equal when ...
g = c
200 -d = 900 -8d . . . . . substitute the above expressions
7d = 700 . . . . . . . . . . add 8d -200
d = 100 . . . . . . . . . divide by 7
100 dispenses from each machine will make the number of candies in the machines equal.