Rick deposited $850 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?  Select.
A) 5
B) 25
C) 50
D) 55
E) 65
5x+15y=850 --1   x+y=60 ---2   multiply eq 2 with 5 and subtract from eq 1   5x+15y=850   5x+5y=300   10y= 550   y=55 and x = 5   therefore $15 bills = 15   ANSWER:55
<result>D</result>
Rick deposited $850 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?