Question 9 — slide 23

Question 9 — slide 24

Question 9 — slide 25

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Teachoo · Class 10 Explore Class 10

Transcript

Question 9 T-shirts marked with numbers 4 to 99 are placed in a box. Gunika is fond of numbers. She randomly takes out a T-shirt from this box. The probability that she gets a T-shirt marked with a number that is either a perfect square or a perfect cube is: (A) (1)/(12) (B) (1)/(32) (C) (11)/(96) (D) (5)/(48) Total number of t-shirts = 99 − 4 + 1 = 96 Perfect square numbers are… 1^(2), 2^(2), 3^(2), 4^(2), 5^(2), 6^(2), 7^(2), 8^(2), 9^(2), 10^(2),… 1, 4, 9, 16, 25, 36, 49, 64, 81, 100, … Perfect cube numbers are… 1^(3), 2^(3), 3^(3), 4^(3), 5^(3),… 1, 8, 27, 64, 125, … Since 64 is common in both, we count it once So, our perfect square or perfect cube numbers between 4 to 99 are 4, 9, 16, 25, 36, 49, 64, 81, 100, 8, 27 Number of perfect square or perfect cube numbers b/w 4 to 99 = 10 Thus, P(getting a perfect squares or perfect cube) = (𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑝𝑒𝑟𝑓𝑒𝑐𝑡 𝑠𝑞𝑢𝑎𝑟𝑒𝑠 𝑜𝑟 𝑝𝑒𝑟𝑓𝑒𝑐𝑡 𝑐𝑢𝑏𝑒)/(𝑇𝑜𝑡𝑎𝑙 𝑛𝑢𝑚𝑏𝑒𝑟𝑠) = (10)/(96) = (𝟓)/(𝟒𝟖) So, the correct answer is (D)

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CA Maninder Singh

CA Maninder Singh is a Chartered Accountant qualified since 2010 and an educator teaching since 2006. At Teachoo, he draws on his accounting and tax experience to explain Accounts, Income Tax and GST through step-by-step lessons and practical examples.

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