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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

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