A box contains 4 defective and 6 non defective bulls. Find the probability that atleast 3 bulbs are defective when 4 bulbs are selected at random.

A box contains 5 defective and 15 non -defective bulbs . , find the probability that atleast 3 bulbs are defective when 4 bulbs are selected at random .

A box contains 5 defective and 15 non -defective bulbs two bulbs are chosen at random . Find the probability that both the bulbs are non - defective .

In a box there are 20 non-defective and some defective bulbs. If the probability that a bulb selected at random from the box found to be defective is 3//8 then, find the number of defective bulbs.

In a box containing 100 bulbs 10 are defective the probability that out of a sample of 5 bulbs none is defective is ?

A lot of 20 bulbs contain 4 defective ones. One bulb is selected at random from the lot. What is the probability that this bulb is defective? Suppose the bulb selected in previous case is not defective and is not replaced. Now one bulb is selected at random from the rest. What is the probability that this bulb is not defective?

A lot of 20 bulbs contain 4 defective ones. One bulb is selected at random from the lot. What is the probability that this bulb is defective? Suppose the bulb selected in previous case is not defective and is not replaced. Now one bulb is selected at random from the rest. What is the probability that this bulb is not defective?

A lot of 20 bulbs contain 4 defective ones. One bulb is selected at random from the lot. What is the probability that this bulb is defective? Suppose the bulb selected in previous case is not defective and is not replaced. Now one bulb is selected at random from the rest. What is the probability that this bulb is not defective?

A lot of 20 bulbs contain 4 defective ones. One bulb is drawn at random from the lot. What is the probability that this bulb is defective? Suppose the bulb is drawn is previous case is not defective and is not replaced. Now one bulb is drawn at random from the rest. What is the probability that this bulb is not defective?