A box contains 90 discs numbered from 1 to 90. If one disc is drawn at random from the box, the probability that it bears a prime number less than 23
A box contains 90 discs numbered from 1 to 90. If one disc is drawn at random from the box, the probability that it bears a prime number less than 23 is
A) 4/17
B) 4/45
C) 4/19
D) 1/2
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Correct option is: B)\(\frac{4}{45}\)
Total No of discs = 90
Prime numbers less than 23 are 2, 3, 5, 7, 11, 13, 17, 19
Total No of prime numbers less than 23 are 8.
\(\therefore\) Probability that selected disc bears a prime number
less than 23 = \(\frac {Total \,No \,of \,prime \,numbers\, less \,than \,23}{Total \,No \,of \,discs}\)
= \(\frac 8{90} = \frac 4{45}\)
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