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

### Instruction:
Betty is saving money for a new wallet which costs $100. Betty has only half of the money she needs. Her parents decided to give her $15 for that purpose, and her grandparents twice as much as her parents. How much more money does Betty need to buy the wallet?

### Response:
 Nusu ya bei ya mkoba inamaanisha $100 / 2 = $<<100/2=50>>50.
Babu na bibi yake Betty walimpa $15 * 2 = $<<15*2=30>>30.
Hivyo Betty anahitaji $50 – $15 – $30 = $<<50-15-30=5>>5 zaidi.