63 dollars
Because if he gets 10 dollars every day there are 7 days in a week so multiply 7x10 to get 70 and if this continues for 3 weeks multiply 70 by 3 to get 210 because he uses 7 dollars every day for three weeks multiply 7 by 21 (for the amount of days in a 3 week period) and you get 147 take 210 and subtract 147 to get 63
