Since there are 7 months from January to July, then Roe's savings for those months sum up to $10 x 7 = $<<7*10=70>>70.

Since there are 4 months from August to November, then her savings for those months sum up to $15 x 4 = $<<4*15=60>>60.

Her total savings from January to November is $70 + $60 = $<<70+60=130>>130.

Therefore, she needs to save $150 - $130 = $<<150-130=20>>20 in December.

# Answer

20
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Roe saved $10 per month from January to July and saved $15 per month from August to November. How much should she save in December so she will have a total savings of $150 in the year?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
20
Roe saved $10 per month from January to July and saved $15 per month from August to November. How much should she save in December so she will have a total savings of $150 in the year?
train