A bag contains 4 white and 3 red balls. Two draws of one bal... | MATH - USE OF PERMUTATIONS AND COMBINATIONS IN PROBABILITY | SolveeIt | Solveeit

Today, August 18

Question

A bag contains 4 white and 3 red balls. Two draws of one ball each are made without replacement. Then the probability that both the balls are red is

A

$\frac { 1 } { 7 }$

B

$\frac { 2 } { 7 }$

C

$\frac { 3 } { 7 }$

D

$\frac { 4 } { 7 }$

Answer

$\frac { 1 } { 7 }$

Explanation

Solution

Required probability $= \frac { { } ^ { 3 } C _ { 1 } } { { } ^ { 7 } C _ { 1 } } \times \frac { { } ^ { 2 } C _ { 1 } } { { } ^ { 6 } C _ { 1 } } = \frac { 1 } { 7 }$ .