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

### Instruction:
Olivia gave William 10 napkins. Amelia also gives William twice the number of napkins Olivia gave him. If William had 15 napkins before, how many napkins does he have now?

### Response:
 Baada ya Olivia kumpa William vitambaa 10, anamaliza na vitambaa 15+10 = <<15+10=25>>25.
Amelia anampa William mara mbili ya idadi ya vitambaa alivyompa Amelia ambayo ni 2*10 = <<10*2=20>>20 vitambaa.
Jumla ya vitambaa William anavyo sasa ni 20+25 = <<20+25=45>>45 vitambaa.