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Numbers are selected at randm, one at time, from the two-digit numbers `00,01,02…,99` with replacement. An event E occurs if the only product of the two digits of a selected number is 18. If four members are selected, find the probability that the event E occurs at least 3 times. |
Answer» Correct Answer - `(97)/((25)^(4))` The given numbers are `00,01,02…,99.` There are total 100 numbers, out of which the numbers, the product of whose digits is 18, are `29,36,63,and 92.` `thereforep=P(E)=(4)/(100)=1/25` ` impliesq=1-p =24/25` From binomial distribution, P(E occuring at least 3 times) =P(E occuring 3 times)+ P (E occuring 4 times) `=""^(4)C_(3)p^(3)q+""^(4)C_(4)p^(4)` `=4xx((1)/(25))^(3)((24)/(25))+((1)/(25))^(4)=(97)/((25)^(4))` |
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