Try this problem from I.S.I. B.Stat TOMATO Objective Problem based on Box and ball Probability.

Box and ball Probability ( B.Stat Objective Problem )


A box contains 100 balls of different colours 28 red 17 blue 21 green 10 white 12 yellow 12 black. The smallest number n such that any n balls drawn from the box will contain at least 15 balls of the same colour is

  • 8
  • 77
  • 11
  • 10

Key Concepts


number Series

Logic

Integers

Check the Answer


But try the problem first…

Answer: 77

Source
Suggested Reading

B.Stat Objective Problem

Challenges and Thrills of Pre-College Mathematics by University Press

Try with Hints


First hint

28 -15 gives 13 and 17-15 gives 2 and 21 -15 gives 6 rest are less than 15

Second Hint

then 100 -13=77 and 100-2=98 and 100-6= 94

Final Step

then smallest number= 77

Subscribe to Cheenta at Youtube