Two friends Richa and Sohan have some savings in their piggy bank. They decided to count the total coins they both had.
Two friends Richa and Sohan have some savings in their piggy bank. They decided to count the total coins they both had. After counting they find that they have fifty ₹ 1 coins, forty eight ₹₹ 2 coins, thirty six ₹₹ 5 coins, twenty eight ₹₹ 10 coins and eight ₹₹ 20 coins. Now, they said to Nisha, their another friends, to choose a coin randomly. Find the probability that the coin chosen is
(i) Rs5 coin
(ii) Rs 20 coin
(iii) Not a Rs 10 coin
(iv) of denomination of atleast ₹10.
(v) of denomination of almost Rs.5.
1 Answers
| Type of coins | ₹1 | ₹2 | ₹5 | ₹10 | ₹20 |
| Total coins | 50 | 48 | 36 | 28 | 8 |
Total no. of coins = 50 + 48 + 36 + 28 + 8 = 170
(i) Probability that chosen coin is Rs 5 = \(\frac{36}{170} = \frac{18}{85}\)
(ii) Probability that chosen coin is Rs 20 = \(\frac 8{170} = \frac 4{85}\)
(iii) Probability that chosen coin is not a Rs 10
\(=1 - \frac{28}{170}\)
\(= 1 - \frac{14}{85} \)
\(= \frac{85 - 14}{85}\)
\(= \frac{71}{85}\)
(iv) Probability that chosen coin is of denomination of at least ₹10
\(=\frac{28+8}{170}\)
\(= \frac{36}{170}\)
\(= \frac {18}{85}\)
(v) Probability that chosen coin is of denomination of at most ₹5
\(=\frac{50 + 48+36}{170}\)
\(= \frac {134}{170}\)
\(= \frac{67}{85}\)