John is 10 years old. His sister is twice his age. When he is 50 years old, how old will his sister be? Let's think step by step and output the final answer after "####".
user
His sister is 10*2= <<10*2=20>>20 years old
Their age difference is 20-10= <<20-10=10>>10 years
Therefore when he is 50 she will be 50+10= <<50+10=60>>60 years old.
#### 60
John is 10 years old. His sister is twice his age. When he is 50 years old, how old will his sister be?
train