Mr. X lost a wallet containing Tk. 120 . Incidentally, he had only notes of Tk. 2 and Tk. 5 denominations in the wallet . If the total number of notes was 30 , how many Tk. 5 denomination notes did he have?

Correct Answer: 20
Let, no. of tk.2 notes x and no. of tk.5 notes y x + y = 30.............(i) so, x = 30 - y 2x + 5y = 120.............(ii) Now, 2(30 - y) + 5y = 120 বা, 60 - 2y + 5y = 120 বা, 3y = 60 so, y = 20