INTRODUCING 5 - days-a-week problem solving session for Math Olympiad and ISI Entrance. Learn More 

April 4, 2020

Box and ball Probability | B.Stat Objective TOMATO Problem 59

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



Check the Answer

Answer: 77

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

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Cheenta. Passion for Mathematics

Advanced Mathematical Science. Taught by olympians, researchers and true masters of the subject.