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

### Instruction:
John is 10 years old. His sister is twice his age. When he is 50 years old, how old will his sister be?

### Response:
 Dada yake ana umri wa 10*2= <<10*2=20>>20.
Tofauti ya umri wao ni 20-10= <<20-10=10>>10 miaka.
Hivyo, akiwa na miaka 50, dada yake atakuwa na miaka 50+10= <<50+10=60>>60.