Ex 14.1, 10 - Chapter 14 Class 10 Probability

Transcript

Ex 14.1, 10 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 will be a 50 p coin? Total number of coins in a piggy bank = 100 + 50 + 20 + 10 = 180 Number of 50 p coins = 100 Probability of getting a 50 p coin = (𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑐𝑜𝑖𝑛𝑠 𝑜𝑓 50𝑝)/(𝑇𝑜𝑡𝑎𝑙 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑐𝑜𝑖𝑛𝑠) = 100/180 = 𝟓/𝟗 Ex 14.1, 10 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 (ii) will not be a ₹ 5 coin? Total number of coins in a piggy bank = 180 Number of ₹ 5 coins = 10 P(not getting a ₹ 5 coin) = 1 – P(getting a ₹ 5 coin) Now, P(getting a ₹ 5 coin) = (𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑐𝑜𝑖𝑛𝑠 𝑜𝑓 ₹ 5 )/(𝑇𝑜𝑡𝑎𝑙 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑐𝑜𝑖𝑛𝑠) = 10/180 = 𝟏/𝟏𝟖 Thus, P(not getting a ₹ 5 coin) = 1 – P(getting a ₹ 5 coin) = 1 – 1/18 = 𝟏𝟕/𝟏𝟖