Download Aptitude Crack
img not found img not found

Permutation and Combination

Q1: A box contains 2 white balls, 3 black balls and 4 red balls. In how many ways can 3 balls be drawn from the box, if at least one black ball is to be included in the draw?

A 32

B 48

C 64

D 96

E None of these

ANS:C - 64

We may have(1 black and 2 non-black) or (2 black and 1 non-black) or (3 black).

 Required number of ways = (3C1 x 6C2) + (3C2 x 6C1) + (3C3)
 
= 3 x 6 x 5 + 3 x 2 x 6 + 1
2 x 1 2 x 1
  = (45 + 18 + 1)
  = 64.



img not found
img

For help Students Orientation
Mcqs Questions

One stop destination for examination, preparation, recruitment, and more. Specially designed online test to solve all your preparation worries. Go wherever you want to and practice whenever you want, using the online test platform.