# math

posted by .

an urn contains 3 blue chips and 7 red chips. sequentially draw 3 chips without replacement. what is the probability that all drawn chips will not be the same color?

• math -

prob ( that they are the same colour)
= BBB or RRR
= (3/10)(2/9)(1/8) + (7/10)(6/9)(5/8)
= 6/720 + 210/720
= 216/720
= 3/10

prob(not the same colour) = 1 - 3/10 = 7/10

• math -

Many thanks!!!

## Similar Questions

1. ### college

a box contains 100 red chips, 100 white chips, and 100 blue chips! without looking, whit is the minimum number of chips that must be drawn out to be assured of getting: a) 30 chip of one color?
2. ### MATH Prob.

a bag contains 7 red chips and 10 blue chips. Two chips are selected randomly without replacement from the bag. what is the probability that both chips are red?
3. ### college

A box contains 4 red and 3 blue chips. What is the probability when 3 chips are selected randomly that all 3 chips will be red if select chips with replacement?
4. ### college math

a bag contains 7 red chips and 9 blue chips. Two chips are selected randomly from the bag without replacement. What is the probability that the two chips are the same color?
5. ### Math

20. A bag contains 7 red chips and 10 blue chips. Two chips are selected randomly without replacement from the bag. What is the probability that both chips are red
6. ### Elementary math College

A bag contains 7 red chips and 9 blue chips. Two chips are selected randomly without replacement from the bag. What is the probability that the two chips are the same color?
7. ### PROBABILITY MATH

A bag contains 10 red chips and 12 blue chips. Two chips are selected randomly without replacement from the bag. What is the probability that the two chips are the same color?
8. ### Probability

A box contains exactly five chips, three red and two white. Chips are randomly • removed one at a time without replacement until all the red chips are drawn or • all the white chips are drawn. What is the probability that the last …