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

### Instruction:
 Bi Davis alitoa vijiti vya barafu 15 kwa kila moja ya makundi 10 katika darasa lake. Ana vijiti vingapi vilivyobaki ikiwa alikuwa na vijiti vya barafu 170?


### Response:
 Bi Davis alitoa jumla ya vijiti vya barafu 15 x 10 = <<15*10=150>>150 kwa makundi 10 katika darasa lake.
Hivyo, amebakiwa na vijiti 170 - 150 = <<170-150=20>>20.