P(Hit) = \(x\)
P(Miss) = \((1-x)\)
To win, Paul must hit the target.
- Probability of Paul hitting in one shot ⇒
- Paul gets one chance, and he must hit the target in that chance.
Net Probability = \(x\)
- Probability of Paul hitting in three shot ⇒
- Paul gets three chances, and to win he must hit at least two of the three chances.
- Case 1: Paul hits twice and misses one chance.
Required Probability = \(x * x * (1-x) * \frac{3!}{2!}\) - Case 2: Paul hits all three shots
Required Probability = \(x * x * x\)
Net Probability = \(3x^2 - 3x^3 + x^3 = 3x^2 - 2x^3\)
Question
\(x > 3x^2 - 2x^3\)
\(2x^3 - 3x^2 + x > 0\)
\(x(2x^2 - 3x + 1) > 0\)
\(x(2x^2 - 2x - x + 1) > 0\)
\(x(2x(x-1) - 1 (x - 1)) > 0\)
\(x(2x-1)(x-1) > 0\)
The critical points are
x = 0
x = 1
x = 1/2
----
-ve -- 0 ---
+ ve --- 1/2 ---
-ve -- 1 ----
+ ve --
As the value of x must be between 0 and 1, the question essentially translates to
Is 0 < x < 1/2 ?
Statement 1(1) x > 0.3 While we know that x > 0.3, we can't for sure say that x < 0.5
For example,
- If x = 0.4, the response to the question Is 0 < x < 1/2 is Yes
- If x = 0.6, The response to the question Is 0 < x < 1/2 is No
Hence, we can eliminate option A, and D
Statement 2(2) x < 0.4 This statement is sufficient. If x < 0.4, the value of x will always lie between 0 and 0.5
Option B