Question

3 Qlue as le Reen and 2 Red, «We 1 th Ree Suppose that 2 marlies aahont selectert f, 2 to have have Both of them the seme elor?

Answer 1

7. 3 blue, 5 green and 4 red.

Number of ways to select r items from n, nCr = n!/(r! x (n-r)!)

7.1 Number of ways to select 1 green and 2 red = Number of ways to select 1 green from 5 x Number of ways to select 2 red from 4

= 5C1 x 4C2

= 5 x 6

= 30

7.2 Number of ways to have both of them of different colors = Number of ways to select 1 blue and 1 green + Number of ways to select 1 green and 1 red + Number of ways to select 1 blue and 1 red

= 3x5 + 5x4 + 3x4

= 47

Number of ways to have both of them of same color = Number of ways to select both blue + Number of ways to select both green + Number of ways to select both red

= 3C2 + 5C2 + 4C2

= 3 + 10 + 6

= 19