Question:
The probability of a man hitting a target is 1 5 . If the man fires 7 times, then what is the probability that he hits the target at least twice?
The probability of a man hitting a target is 1 5 . If the man fires 7 times, then what is the probability that he hits the target at least twice?
Options:
- a) 1 3 5 4 5 6
- b) 1 3 5 4 5 7
- c) 1 11 5 4 5 6
- d) 1 11 5 4 5 7
- a) 1 3 5 4 5 6
- b) 1 3 5 4 5 7
- c) 1 11 5 4 5 6
- d) 1 11 5 4 5 7
correct answer : c)
Explanation:
P(X ³
2) = 1 – P(X = 0) -P(X = 1)
= 1 1
5
4
5
1
5
4
7
7
0
07
7
1
16
–
–
CC
= 1 4
5
4
5
7
5
6
–
+
= 1 11
5
4
5
6
–
P(X ³
2) = 1 – P(X = 0) -P(X = 1)
= 1 1
5
4
5
1
5
4
7
7
0
07
7
1
16
–
–
CC
= 1 4
5
4
5
7
5
6
–
+
= 1 11
5
4
5
6
–