A box contains 12 transistors, 3 of which are defective. If 3 are selected at random, find the probability?
All are Defective =
None are defective=

I came up with answers I dont think i am correct thank you
All = 1/288
None = 7/24

Question

A box contains 12 transistors, 3 of which are defective. If 3 are selected at random, find the probability?
All are Defective =
None are defective=

I came up with answers I dont think i am correct thank you
All = 1/288
None = 7/24

anonymous · Answer

A box contains 30 transistors, 6 of which are defective. If 6 are selected at random find the probability that 

a) all are defective. 

The probability that the 1st selection will be defective is 6/30, 
the probability that the 2nd selection will be defective is 5/29, 
the probability that the 3rd selection will be defective is 4/28, 
etc., the probability that the 6th selection will be defective is 1/25. 

Multiply those probabilities: 

6/30 * 5/29 * 4/28 * 3/27 * 2/26 * 1/25 

= 720 / 427518000 

= 1 / 593775.

anonymous · Answer