Human: On Blacks, Martha goes to the mall to buy clothes on sale. For every 2 jackets she buys, she gets 1 free jacket. For every 3 t-shirts she buys, she gets 1 free t-shirt. Martha decides to buy 4 jackets and 9 t-shirts. How many clothes will she take home? Assistant:
For buying 4 jackets Martha gets 4 jackets / 2 = 2 jackets for free
For buying 9 t-shirts, Martha gets 9 t-shirts/ 3 = 3 t-shirts for free
Adding the free jackets, Martha gets 4 jackets + 2 jackets = 6 jackets
Adding the free t-shirts, Martha gets 9 t-shirts + 3 t-shirts = 12 t-shirts.
In total, Martha will take home 6 jackets + 12 t-shirts = 18 clothes