UPSC NDA Math Model Paper 2

Let's say that A is the event of drawing a 10 and B be the event of drawing a spade.
Probability of drawing a 10=P(A)=

4

52

.
Probability of drawing a spade =P(B)=

13

52.

Probability of drawing a 10 of spade =P(A∩B)=

1

52.

∴ Probability of drawing a 10 or a spade =P(A∪B)=P(A)+P(B)−P(A∩B)

4

52

+

13

52

−

1

52

=

16

52

=

4

13