A owes B Rs.50. He agrees to pay B over a number of consecutive days on a Monday, paying single note or Rs.10 or Rs.20 on each day. In how many different ways can A repay B.
Pick one
A) 2  B) 8  C) 9  D) 6  E) 5
He can pay by all 10 rupee notes = 1 way   3 Ten rupee + 1 twenty rupee = 4!3!×1!4!3!×1! = 4 ways   1 Ten rupee + 2 twenty rupee notes = 3!2!×1!3!2!×1! = 3 ways   Total ways = 1 + 4 + 3= 
<gadget id="calculator">1 + 4 + 3</gadget>
<output>8</output>
8   Answer:8
<result>B</result>
A owes B Rs.50. He agrees to pay B over a number of consecutive days on a Monday, paying single note or Rs.10 or Rs.20 on each day. In how many different ways can A repay B.