The probability of a shooter hitting a target is 0.75. How many minim...
Given
Probability of success, p = 0.75
Concept used:
The binomial distribution formula is
P(X = x) = ncx qn – x px
Where,
P(X) = Probability of a success on an individual trial
p = Probability of successes
x = Number of success
q = Probability of failure or q = 1 – p
n = Number of trials
ncx = n!/(n – x)!x!
Calculation:
Here, p = 0.75 = (75/100) = ¾
So, probability of missed target = q = 1 – ¾
⇒ ¼
P(X = r) = ncx qn – x px, x = 0, 1, 2, ...., n
⇒ ncx(1/4)n – x (3/4)x = ncx(3x/4n)
Now, P(hitting the target at least once) > (1 – 0.01) = 0.99
⇒ P(x ≥ 1) > 0.99
So,1 – P (x = 0) > 0.99
⇒1 – nc0(1/4n) > 0.99
⇒ nc0(1/4n) < (1="" –="" />
⇒ nc0(1/4n) < />
⇒ (1/4)n < />
⇒ 4n > 1/0.01
⇒ 4n > 1/(1/100)
⇒ 4n > 100
The minimum value of n to satisfy the inequality (1) is 4.
∴ The shooter must fire 4 times