# Homework

• Feb 9th 2006, 08:06 PM
batman123
Homework

A shop that produces custom kitchen cabinets has two employees, "S" and "C". 95% of "C" work is satisfactory and 10% of "S" work is unsatisfactory. 60% of the shops cabinets are made by "C" (the rest by "S"). Find the following probabilities: (a) an unsatisfactory cabinet was made by "C"; (b) a cabinet is unsatisfactory.

A chapter of union Local 715 has 73 members. In how may different ways can the chapter select a president, a vice-president, a secretary, and a treasurer?

A cellular phone manufacturer randomly selects 5 out of every 50 phone from the assemble line and test them. If at leas 4 of the 5 pass inspection, the batch of 50 is considered acceptable. find the probability that a batch of 50 phones is considered acceptable given the following additional information: (a) the batch of 50 phones contains 2 defectives; (b) the batch of 50 phone containe no defectives (c) the batch of 50 phones contains 3 defectives.

A new factory machine manfactures computer chips in malfunctioning and has a 20% defect rate. If 5 chips are randomly selected from the machine, find the following probabilities. (a) non are defective; (b) less tha 2 are defective.

The insurance industry has found that the probability is .9 that a life insurance applicant will qualify at the regular rates. Find the probability that of the next 10 applicants for life incurance, the following numbers will qualify at the regular rates. (a) exactly 9; (b) at least 9.
• Feb 10th 2006, 01:42 AM
CaptainBlack
Quote:

Originally Posted by batman123
In a hospital unit there are 8 nurses and 5 physicians. 7 nurses and 3 physicans are females. If a person is selected at random find the probability that the subject is a nurse or a male.

There are 13 people in the unit (8 nurses and 5 physicians), of these 10
are female (7 nurses and 3 physicians), so there are 3 male (1 nurse and 2
physicians)

Probability of choosing a male = (number of males)/(number of people)=3/13.

RonL
• Feb 10th 2006, 03:34 AM
CaptainBlack
Quote:

Originally Posted by batman123
Two cards are drawn without replacement from an standard deck of cards.
find the followng probabilities (a) both cards are diamonds; (b) an ace and a four are drawn; (c) the second is a club, given that the first is a club; (d) the second card is 9 given that the first card was a 3.

Probability that both are diamonds P(first=D and second=D) is the probability
that the first is a diamond times the probability that the second is a diamond
given that the first is a diamond

P(first=D and second=D)=P(first=D)P(second=D|first=D)

P(first=D)=13/52 (as there are 13 diamonds in the deck of 52 cards)
P(second=D|fist=D)=12/51 (as there are 12 diamonds left out of 51 cards remaining)

so:

P(first=D and second=D)=(12x13)/(51x52).

RonL