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?

Answer 1

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

Answer 2

Many thanks!!!