Let the number of days be x

He saves $50-$15=$<<50-15=35>>35 each day

After x days he had saved $35*x=$35x

His mom doubled his savings to give $35x*2=$70x

His dad added $10 to give $70x+$10=$500

Subtracting 10 from both sides of the equation formed gives $70x=490

Dividing both sides by $70 give x=7 days

# Answer

7
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Ben starts each day with $50, spends $15 every day and saves the rest. After a few days, his mom doubled his total savings and his dad gave him an additional $10. If he now has $500, How many days have elapsed?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
7
Ben starts each day with $50, spends $15 every day and saves the rest. After a few days, his mom doubled his total savings and his dad gave him an additional $10. If he now has $500, How many days have elapsed?
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