Assume that on a n average on telephone number out of 15 called between 2 P.M. and 3 P.M. on week days s busy. What is the probability that if six random selected telephone numbers are calld, at least 3 of them will be?

What is the probability that a number selected from the numbers 1,\ 2,\ 3,\ ddot,\ 15 is a multiple of 4?

What is the probability that a number selected from the numbers 1,\ 2,\ 3,\ .......,\ 15 is a multiple of 4?

On dialling certain telephone numbers, assume that on an average one telephone number out of five is busy, ten telephone numbers are randomly selected and dialled. Find the probability that at least threeof them will be busy

What is the probability that a number selected at random from the number 1,\ 2,\ 2,\ 3,\ 3,\ 3,\ 4,\ 4,\ 4,\ 4 will be their average?

Nine cards (identical in all respects) are numbered 2 to 10. A card is selected from them at random. Find the probability that the card selected will be : an even number and a multiple of 3.

Nine cards (identical in all respects) are numbered 2 to 10. A card is selected from them at random. Find the probability that the card selected will be : -->an even number or a multiple of 3.

Nine cards (identical in all respects) are numbered 2 to 10. A card is selected from them at random. Find the probability that the card selected will be : a multiple of 3.

If the number of telephone calls an operator receives between 10:00 am to 10:10 pm follow poisson distribution with mean 3. The probability that the operator receives one call during that interval the next day is

Suppose that the number of telephone calls coming into a telephone exchange between 10 A.M. and 11 A.M., say, X_(1) is a random variable with possion distribution with parameter 2. Similarly the number of calls arriving between 11 A.M. and 12 noon, say X_(2) also follows a poisson distribution with parameter 6. If X_(1) and X_(2) are independent, what is the probability that more than 5 calls come in between 10 A.M. and 12 noon.

A colony of bacteria numbers 2,000 at 1 P.M. and increases 20 percent per hour . What is the population at 4 P.M. that same day ?