Greenhill
posted by Lorna on .
Abag contains 11red beads 4 green beads 1 purple bead. Two beads are drawn without replacement in the bag. A). Calculate probability ttwo beads are same colour. And. B) calculate probability purple bead is not taken.

You'll get better results if you follow directions and put the SCHOOL SUBJECT in that box, not the name of your school.

a) could be either RR or GG
prob(RR = (11/16)(10/15) = 11/24
prob(GG) = (4/16)(3/15) = 9/20
prob(2 same colour) = 11/24 + 9/20 = 109/120
prob (one purple , one none) = (1/16)(15/15) + 15/16)(1/15) = 1/8
prob(NOT a purple) = 1  1/8 = 7/8