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A box contains 90 discs which are numbered from 1 to 90. If one disc is drawn at random from the box, find the probability that it bears (i) a two-digit number (ii) a perfect square number. (iii) a number divisible by 5. |
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Answer» (i) 10,11,12 … 90 are two digit numbers. There are 81 numbers. So, Probability of getting a two-digit number \(\frac{81}{90}=\frac{9}{10}\) (ii) 1, 4, 9,16,25,36,49,64,81 are perfect squares. So, Probability of getting a perfect square number. \(\frac{9}{90}=\frac{1}{10}\) (iii) 5, 10,15 ... 90 are divisible by 5. There are 18 outcomes. So,Probability of getting a number divisible by 5. = \(\frac{18}{90}=\frac{1}{5}\) |
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