Question

A piggy bank contains hundred 50 p coins, seventy ₹1 coin, fifty ₹2 coins and thirty ₹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 ₹5 coin?

Answer 1

Number of 50 p coins = 100.

Number of ₹1 coins = 70.

Number of ₹2 coins = 50.

Number of ₹5 coins = 30.

Thus, total number of outcomes = 250.

Let E₂ be the event of not getting a ₹5 coin.

Number of favourable outcomes = 250 − 30 = 220

∴ P(not getting a ₹5 coin) = P(E₂) = `("Number of outcomes favourable to" E_2)/"Number of all possible outcomes"`

`= 220/250 = 22/25`

Thus, the probability that the coin will not be a ₹5 coin is `22/25`.