The number of doughnuts in bags is 4 times the number of bags of doughnuts. So the number in B bags of doughnuts will be
... 4B
The number of doughnuts in cartons is 10 times the number of cartons of doughnuts, so the number in C cartons will be
... 10C
The total number of doughnuts (T) is the sum of those in bags and those in cartons:
... T = 4B +10C