Probability ncert solutions Chapter 15 Exercise 15.1 Question 10
10. 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
(i) will be a 50p coin. (ii) will not be a Rs 5 coin
Let E be the event that 50p coin falls out.
Number of outcomes favorable to event E =Total number of 50p coins=100
Total number of possible outcomes=total number of coins=100+50+20+10=180
P(E)=(Number of outcomes favorable to event E)/Total number of possible outcomes
Let F be the event that the coin falls out is not Rs 5.
Number of possible outcomes favorable to event F=Total number of coins except Rs 5 coins=100+50+20=170
Total number of possible outcomes=Number of coins=100+50+20+10=180
P(F)=Number of possible outcomes favorable to event F/Total number of possible outcomes