<human>:  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?
<bot>: Define a variable ** Let the number of days be x
How much does Ben save each day? ** He saves $50-$15=$<<50-15=35>>35 each day
How much did Ben save after x days? ** After x days he had saved $35*x=$35x
How much did Ben's mom give him? ** His mom doubled his savings to give $35x*2=$70x
How much did Ben's dad give him? ** His dad added $10 to give $70x+$10=$500
How much did Ben's dad give him? ** Subtracting 10 from both sides of the equation formed gives $70x=490
How many days have elapsed? ** Dividing both sides by $70 give x=7 days
#### 7