TopsOJ Summer 2025 - Guts Round - Problem 6

Issac has made 3 batches of cookie dough where each batch of cookie dough is 6 cups. Mary, Issac's 5 year old daughter, loves to secretly eat cookie dough when Issac isn't looking. Issac has left the house for 4 hours to buy more flour. If Mary eats at a rate of 1.5 cup of cookie dough every hour, how many cups of cookie dough will be left over when Issac returns?