Probability Part 1

X: Mr. A selected wining horse
X : Mr. A did not select wining horse
Mr. A selected two horses, now probability of not wining the first horse which Mr. A choses=
‌

4

5

And probability of not wining the second horse also which Mr. A choses =‌

3

4

(Here Mr. A out of remaining 4 horses choses one horse among 3 horses which did not win)
∴P(X)=‌

4

5

×‌

3

4

∴P(X)=1−P(X)
=1−‌

4

5

×‌

3

4

=1−‌

3

5

=‌

2

5