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

### Instruction:
 Unaweza kupunguza bei kwa 20% ikiwa unanunua zaidi ya vifaa kumi na tano vya kesi ya iPhone. Ikiwa unalipa $500 kununua vitengo 18, bei ya awali ni kiasi gani?


### Response:
 Ikiwa unanunua vitengo 18, asilimia ya bei jumla inapungua hadi 100% - 20% = 80%
Ikiwa 80% ni sawa na $500, basi 100% ni sawa na 100%/80% * $500 = $625