Below is an instruction that describes a task. Write a response that appropriately completes the request in Swahili. Please answer in Swahili.

### Instruction:
4 friends went to buy from a clothes shop. Every item was 50% off.  All four friends decided to buy a t-shirt. The original price of the t-shirt was 20 dollars. How much money did they spend in total?

### Response:
 Baada ya punguzo la 50%, fulana iligharimu 20 * 0.5 = $<<20*0.5=10>>10.
Kwa hivyo jumla, marafiki 4 walitumia 4 * $10 = $<<4*10=40>>40 kwa fulana.