A shelf in the Metro Department Store contains 95 colored ink cartridges for a popular ink-jet printer. Six of the cartridges are defective.

a) customer selects 2 cartridges at random, what is the probability that both are defective? (round answer to 5 decimal places)

b) customer selects 2 cartridges at random, what is the probability that at least 1 is defective? (round answer to 3 decimal places)

Question

A shelf in the Metro Department Store contains 95 colored ink cartridges for a popular ink-jet printer. Six of the cartridges are defective.

a) customer selects 2 cartridges at random, what is the probability that both are defective? (round answer to 5 decimal places)

b) customer selects 2 cartridges at random, what is the probability that at least 1 is defective? (round answer to 3 decimal places)

anonymous · Answer

I'm pretty sure A) is (6/95)(5/94)=.00335946 and it's saying the answer is wrong when rounded

anonymous · Answer

B) 1-(answer to A). Need help!

kropot72 · Answer

The answer to a) is given by
$$\frac{6\times5}{95\times94}$$
What was your result when rounded?

anonymous · Answer

I figured out A, but B isn't the right equation I don't think

kropot72 · Answer

b) The answer is not found by subtracting the answer to a) from 1.
The solution can be found from:
P(at least one defective) = 1 - P(0 defective)
$$P(0\ defective)=\frac{89\times88}{95\times94}=you\ can\ calculate$$

anonymous · Answer

got it, thanks!

kropot72 · Answer

Good. What was your result?