Answer:
the required probability is 0.0071
Step-by-step explanation:
Given the data in the question;
we have narrowed the possibilities down to 4 people, 5 weapons, and 7 rooms.
so total number of combinations for the narrowed down metrics is computed as follows;
using multiplication rule:
⇒ 4 × 5 × 7 = 140 ways
Now, the probability of making a random guess from our narrowed down choices as well as getting the guess correct will be;
⇒ 1 / 140
{ assuming that the narrowed down choices have within it the correction combination }
= 0.007142 ≈ 0.0071 { four decimal place }
∴ the required probability is 0.0071