# Probability

A box contains 20 balls out of which 12 are red and 8 are green . 5 balls are randomly drawn from the box with replacement . What is the probability that at most 3 balls are green in colour ?

A) 253/3125

B) 423/625

C) 272/3125

D) None

Forward This Problem to Friend http://www.solvemaths.in/probability-13/ProbabilityA box contains 20 balls out of which 12 are red and 8 are green . 5 balls are randomly drawn from the box with replacement . What is the probability that at most 3 balls are green in colour ?
A) 253/3125
B) 423/625
C) 272/3125
D) None

dinesh
ppboomshankar@gmail.comSubscriberSOLVE - ΜΔΓΗŠ
The answer is explained below:

P : Probability

G: Green ball

R: Red ball

Most X = lesser than and equal to X => X is number of balls of any color

P(most 3 G)= P(0 G) + P(1 G) + P(2 G) + P(3 G)

P(<=3G) = (12C5 + 12C4*8C1 + 12C3*8C2 + 12C2*8C3)/20C5 [nCr = {n!/(r!*(n-r)!)]

Answer: d) None