Question

A piggy bank contains hundred 50p coins, fifty Re 1 coins, twenty Rs. 2 coins and ten Rs. 5 coins. If it is equally likely that one of the coins walnt out when the bank is turned upside down, what is the probability that the coin (i) will be a 50p coin? and (ii) will not be Rs. 5 coin?

Answer 1

Answer:

Number of 50 ps coins =100 

Number of Re. 1 coins =50

Number of Rs. 2 coins =20

Number of Rs. 5 coins =10

∴ Total number of coins, n(S)=180

Possibility of one Rs. 5 coin:

n(B)=180−10=170

(∵ 10 coins are Rs. 5) 

∴ Probability, P(B)=n(S)n(B)=180170=1817

Answer 2

Given:-

• A piggy bank contains hundred 50p coins, fifty Re 1 coins, twenty Rs. 2 coins and ten Rs. 5 coins.

To find:-

• (i) will be a 50 p coin?
• (ii) will not be a Rs 5 coin?

Solution:-

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Total number of coins in the piggy bank = 100 + 50 + 20 + 10 = 180

∴ Total number of elementary events = 180

(i) There are one hundred 50 paise coins in the piggy bank.

∴ Favourable number of elementary events = 100

Hence, P(falling out of a 50p coin) = 100/180 = 5/9

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(ii) There are 100 + 50 + 20,i.e., 170 coins other than Rs 5 coin.

∴ Favourable number of elementary events = 170

Hence, P(falling out of a coin other than Rs 5 coin) = 170/180 = 17/18

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