Question

A piggy bank contains hundred 50 p 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 50 p coin? (ii) Will not be a Rs.5 coin?

Answer 1

Answer:

$1)\dfrac{5}{9}$

$2)\dfrac{17}{18}$

Explanation:

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

= 180

(i) Number of 50 p coins = 100

$\sf{}Probability\ of\ getting\ 50\ p\ coins = \dfrac{Number\ of\ favourable \ outcomes}{Total\ number\ of\ possible\ outcomes}$

$\sf{}\Rightarrow \dfrac{100}{180}$

$\sf{}\Rightarrow \dfrac{10}{18}$

$\sf{}\Rightarrow \dfrac{5}{9}$

ii) Number of Rs 5 coins = 10

$\sf{}Probability\ of\ getting\ 5\ p\ coins = \dfrac{Number\ of\ favourable \ outcomes}{Total\ number\ of\ possible\ outcomes}$

$\sf{}\Rightarrow \dfrac{10}{180}$

$\sf{}\Rightarrow \dfrac{1}{18}$

Probability of not getting a Rs 5 coin

$\sf{}\Rightarrow1-\dfrac{1}{18}$

$\sf{}\Rightarrow\dfrac{1\times18-1\times1}{18}$

$\sf{}\Rightarrow\dfrac{18-1}{18}$

$\sf{}\Rightarrow\dfrac{17}{18}$

Answer 2

Given :-

Piggy bank contains -

• Number of 50 P Coins = 100
• Number of 1 RS coins = 50
• Number of 2 RS coins = 20
• Number of 5 RS coins = 10

To FinD :-

1. Probability of Getting 50 P coin
2. Probability of not getting 5 RS coin.

Solution :-

Number of Total coins in Piggy bank = 100 + 50 + 20 + 10

= 180 Coins

(I) Number of 50 P coin = 100

$\bold{Probability \:of \:getting\: 50\: P\: coin =\frac{Number\:Of\: Favourable\:Outcomes}{Total\: Number\:Of\: Possible\:Outcomes}}$

$→ \frac{100}{180}$

$→ \frac{10}{18}$

$→ \frac{5}{9 }$

(ii) Number of 5 Rs coins = 10

$\bold{Probability \:of \:getting\: 5\: rs\: coin =\frac{Number\:Of\: Favourable\:Outcomes}{Total\: Number\:Of\: Possible\:Outcomes}}$

$→ \frac{10}{180}$

$→ \frac{1}{18}$

Probability of Not getting 5 RS coin →

$→ 1 - \frac{1}{18}$

$→ \frac{18 - 1}{18}$

$→ \frac{17}{18}$