Marble samplesIf a bag of marbles containing 15 marbles has

Marble samples—If a bag of marbles containing 15 marbles has 3 yellow, 4 white, and 8 blue marbles, how many samples of 2 can be drawn in which both marbles are blue?

Solution

given 15 marbles has 3 yellow, 4 white, and 8 blue marbles

2 marbles are drawn from 8 blue marbles is ⁸C₂ = 8*7/2 = 28

2 marbles are drawn from total 15 marbles is ¹⁵C₂ = 15*14/2 = 105

total samples of 2 can be drawn in which both marbles are blue

_{=  2 marbles are drawn from 8 blue marbles / 2 marbles are drawn from total 15 marbles}

     = 28/105