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

### Instruction:
Joy has 30 pencils, and Colleen has 50 pencils. If they bought the pencils at $4 each at the store, how much more money did Colleen pay than Joy for her pencils?

### Response:
 Idadi ya kalamu ambazo Colleen ana zaidi ya Joy ni 50-30 = <<50-30=20>>20 kalamu
Kwa kuwa Colleen alinunua kila kalamu kwa $4, gharama ya jumla ya kalamu 20 zaidi ni 20*$4 =$<<20*4=80>>80