Tuesday

How many different amounts of postage?

I have four 3 cents stamps and three 5 cents stamp using one or more of these stamps. Using one or more of these stamps. How many different amounts of postage can I make?

Four 3 cents stamps can be used in 4 different ways (using 1 stamp, 2 stamps, 3 stamps and 4 stamps at a time)

Similarly Three 5 cents stamps can be used in 3 different ways.

So both stamps together can be used in 4*3 = 12 different ways. 
=> Total different ways = 4+3+12=19 

19 different amounts of postage can be made using the stamps.






5 comments :

  1. ? Why did you do 4*3, then take the product and add 7?

    ReplyDelete
    Replies
    1. Dear Unknown, Maybe this helps.
      Each stamp alone = 4 ways + 3 ways = 7 ways
      Stamps together = 4 ways x 3 ways = 12 ways
      Total = 12 ways + 4 ways + 3 ways = 19 ways

      Delete
  2. what happened to the 5 cents stamps?

    ReplyDelete