Rick deposited $800 to his bank account using $5 and $15 dollar bills only. If Rick came to the bank with 70 bills and left with 10 bills only, how many $15 dollar billsმ did he deposit?
Choose the correct choice from the following answers
A) 5. B) 25. C) 50. D) 55. E) 65.
5x+15y=800 --1   x+y=60 ---2   multiply eq 2 with 5 and subtract from eq 1   5x+15y=800   5x+5y=300   10y= 500   y=50 and x = 10   therefore $15 bills = 50   Answer 50.
<result>C</result>
Rick deposited $800 to his bank account using $5 and $15 dollar bills only. If Rick came to the bank with 70 bills and left with 10 bills only, how many $15 dollar billsმ did he deposit?