Question

A piggy bank contains hundred coins of Rs. 1, twenty five coins of Rs. 2, fifteen coins of Rs. 5 and ten coins of Rs. 10. If it is equally likely that one coin will fall, when the bank is turned upside down, what is the probability that the coin
(i) Will be a Rs. 2 coin?
(ii) Will not be a Rs. 5 coin?

Answer 1

Probability of an event is defined as the ratio of favorable outcomes to the total outcomes.

(i) Probability that the fallen coin is $Rs.2$ coin is the ratio of number of $Rs.2$ coins and total number of coins.

$P_2=\frac{25}{100+25+15+10}=\frac{1}{6}$

(ii) Probability that the fallen coin is $Rs.5$ coin is the ratio of number of $Rs.5$ coins and total number of coins.

$P_5=\frac{15}{100+25+15+10}=\frac{1}{10}$