# finite math

posted by .

a box contains 40 computer disks, 5 are defective. Three disks are selected from the box without replacement and regard to order. what is the probability that

a. all three of the disks are defective

b. none of the three disks are defective

c. exactly one of the three disks is defective

d. at least one of the three disks works

• finite math -

d - defective
g -good

a) prob(ddd) = (5/40)(4/39)(3/38) = ....

b) prob(ggg) = (35/40)(34/39)(33/38) = ....

c) prob(dgg) + prob(gdg) + prob(ggd) = 3(5/40)(35/39)(34/38) = ...

d) 1 - prob(ddd) = 1 - (35/40)(34/39)(33/38)

## Similar Questions

1. ### Math Finite

A box contains 15 pens of which 4 are defective. A random sample of 3 pens is taken without replacement and without regard to order. What is the probability of selecting at least one defective pen?
2. ### statistics

A manufacturer of computer disks has a historical defective rate of .001. What is the probability that in a batch oof 1000 disks, 2 would be defective?
3. ### math

Numbered disks are placed in a box and one disk is selected at random. There are 6 red disks numbered 1 through 6, and 7 yellow disks numbered 7 through 13. In an experiment a disk is selected, the number and color noted, replaced, …
4. ### Statistics

A box contains 12 lights bulbs, of which 4 are defective. All bulbs look alike and have equal chance of being chosen. 3 light bulbs are selected from the box to check the quality. a. List all the possible outcomes b. find the probability …
5. ### Statistics

A box contains 10 items, of which 3 are defective and 7 are non-defective. Two items are randomly selected, one at a time, with replacement, and x is the number of defective items in the sample. To look up the probability of a defective …
6. ### Statistics/Probability

In the production of a particular model of cell phones, it is found that 5% are defective. Cellular phones are selected at random and put into boxes of 10. If a box is selected at random, find the probability that it contains. (i) …
7. ### Finite Math

A box contains two defective Christmas tree lights that have been inadvertently mixed with eight nondefective lights. If the lights are selected one at a time without replacement and tested until both defective lights are found, what …
8. ### Probabilities

Need some help please! A box contains four good light bulbs and three defective ones. Bulbs are selected one at a time (without replacement). Find the probability that the second defective bulb is found on the third selection.
9. ### Statistics

In a shipment of 21 parts, four of the parts are defective. If three parts are selected at random without replacement, find the probability that : a.) All three parts selected are defective. 4/21*3/20*2/19=.003 b.) None of the tree …
10. ### Math 120

A box contains 10 â€‹transistors,4 of which are defective. If 4 are selected atâ€‹ random, find the probability that a. All are defective. b. None are defective.

More Similar Questions