I'm completely lost with this math problem: On Thursday, Joe caught 3 pounds of crawfish.  He caught 4 times that amount on Friday and half the amount of his Friday's catch on Saturday.  If 1 serving of crawfish is 3 pounds, how many servings does he have?
Can you give me a hand?
He caught 3 pounds on Thursday and caught 4 times the amount on Friday for a total of 3*4 = 12 pounds
On Saturday, he caught half the amount of the 12 pounds he caught on Friday so he caught 12/2 = 6 pounds
In three days he has caught 3+12+6 = 21 pounds of crawfish
3 pounds is a serving and he caught 21 pounds so he has 21/3 = 7 servings of crawfish