Question

From eighty cards numbered 1 to 80, two cards are selected randomly. The probability that both the cards have the numbers divisible by 4 is given by

• A. $\frac { 21 } { 316 }$
• B. $\frac { 19 } { 316 }$
• C. $\frac { 1 } { 4 }$
• D. None of these

Answer 1

Answer: (B)

$\frac { 19 } { 316 }$

Answer 2

Total number of ways $= { } ^ { 80 } C _ { 2 }$

and favorable ways$= { } ^ { 20 } C _ { 2 }$

∴ Required probability $P = \frac { { } ^ { 20 } C _ { 2 } } { { } ^ { 80 } C _ { 2 } } = \frac { 19 } { 316 }$.