Difficulty: Easy
Correct Answer: 1 - (0.7)^10
Explanation:
Introduction / Context:
With independent trials, the probability of “at least one success” is one minus the probability of “no success at all.” Here, success = hit, p = 0.3 per shot, n = 10 shots.
Given Data / Assumptions:
Concept / Approach:
P(≥1 hit) = 1 − P(0 hits) = 1 − q^n with q = 0.7.
Step-by-Step Solution:
P(0 hits) = (0.7)^{10}.Therefore P(≥1 hit) = 1 − (0.7)^{10}.
Verification / Alternative check:
As p increases or n grows, the probability approaches 1, consistent with intuition.
Why Other Options Are Wrong:
(0.7)^10 is the probability of zero hits; (0.3)^10 is “all hits” if inverted (actually all-hit probability is (0.3)^{10}); 1 is only true in the limit, not exactly; 1 − (0.3)^10 is not the correct complement.
Common Pitfalls:
Confusing “at least one” with “exactly one,” or complementing the wrong event.
Final Answer:
1 - (0.7)^10
Discussion & Comments