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

### Instruction:
Mark wants to tip his server 20% on a $200 check. If his friend agrees to kick in $10, how much should Mark add?

### Response:
 Kwanza tafuta jumla ya kiasi cha mshahara: 20% * $200 = $<<20*.01*200=40>>40
Kisha toa mchango wa rafiki: $40 - $10 = $<<40-10=30>>30