each of two friends has 20 stamps and 10 post cards.we call an exchange 'fair' if they exchange a stamp for a stamp or postcard for a post card.how many ways are there to carry out one fair exchange between these two friends?

• 500 ways
  for 1 stamp of a friend the other has 20 ways of fair exchange
  for 20 stamps the fair exchanges are 20*20=400
  similarly fair exchanges of postcards are 10*10=100
  total 500 ways
• 11 years agoHelpfull: Yes(25) No(0)
• 20!*10!
  stamps 20 20
  cards 10 10
  for 1 card of ram 10 ways to exchange and for the 2nd card 9 ways and so on..
  hence 10! for cards and 20! for stamps
• 11 years agoHelpfull: Yes(4) No(2)
• What is coorect ans??@REDDY
• 11 years agoHelpfull: Yes(2) No(0)
• 500 ways
  for 1 stamp 20 ways
  for 20 stamps 20 ways
  for 10 posts 10 ways
  total ways=400+100
• 11 years agoHelpfull: Yes(1) No(0)
• @REDDR SIRI I think its 30.......am I right????
• 11 years agoHelpfull: Yes(0) No(2)
• 500 is the correct ans
• 11 years agoHelpfull: Yes(0) No(2)
• it is a fair exchane. ithink in is(20+10)=30
• 11 years agoHelpfull: Yes(0) No(1)
• i think according to kranthi answer mit be 20^20*10^10
• 11 years agoHelpfull: Yes(0) No(1)