Matt can make a batch of a dozen cookies using 2 pounds of flour.  He uses 4 bags of flour each weighing 5 pounds.  If Jim eats 15 cookies how many cookies are left?
Matt used 4*5=<<4*5=20>>20 pounds of flour
That means he made 20/2=<<20/2=10>>10 batches
So he cooked 10*12=<<10*12=120>>120 cookies
After Jim eats 15 there are 120-15=<<120-15=105>>105 cookies left
#### 105