Question

A bag contains 5 balls 2 are drawn at random and found to be white. Then probability that all balls are white is

• A. ½
• B. 1/3
• C. 2/3
• D. ¼

Answer 1

Answer: (A)

½

Answer 2

0	1	2	3	4	5
E0	E1	E2	E3	E4	E5
$\frac { 1 } { 6 }$	$\frac { 1 } { 6 }$	$\frac { 1 } { 6 }$	$\frac { 1 } { 6 }$	$\frac { 1 } { 6 }$	$\frac { 1 } { 6 }$

P(E₅) = $\frac { 1 } { 6 }$+$\frac { 1 } { 6 }$+$\frac { 1 } { 6 }$ = $\frac { 3 } { 6 } + \frac { 1 } { 2 }$ .