Rick deposited $600 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?
Options:	A) 5.	B) 25.	C) 30.	D) 55.	E) 65.
5x+15y=600 --1   x+y=60 ---2   multiply eq 2 with 5 and subtract from eq 1   5x+15y=600   5x+5y=300   10y= 300   y=30 and x = 30   therefore $15 bills = 30   Answer 30.
<result>C</result>
Rick deposited $600 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?