Juan needs 10 half-gallons of milk to bake 40 cookies with. How many half-gallons of milk does Juan need to bake 200 dozen cookies?
If 10 half-gallons of milk bake 40 cookies, then one half-gallon of milk bakes 40/10 = 4 cookies.
If one half-gallon of milk bakes 4 cookies. to bake 200 cookies, you'll need 200/4 = <<200/4=50>>50 half-gallons of milk
#### 50