Each packet of washing powder carries a token and four tokens can be exchanged for a free packet. How many free packets will I receive
if I buy 64 packets?
Answer :
​(1) 64 packets have 64 tokens. Thus you can get 64/4=16 free packets.
(2) From the 16 packets you will get 16 tokens. These can be exchanged for another 16/4=4 packets.
(3) From the 4 packets you will get 4 tokens which can be exchanged for a free packet.
In total, you will get 16+4+1=21 free packets.