10(ii) A piggy bank contains hundred 50p coins, fifty Rs 1 coins, twenty Rs 2 coins and ten Rs 5 coins. If it is equally likely that one of the coins will fall out when the bank is turned upside down, what is the probability that the coin will not be a Rs 5 coin?
Total number of coins in the piggy bank = 100+50+20+10 = 180
Let F be the event of getting an Rs. 5 coin.
Number of possible outcomes = 180
Number of outcomes favourable to event E = 10
Therefore, the probability of not getting an Rs. 5 coin is