Question

🚪 A building has 20 doors numbered 1 through 20. What is the probability of randomly opening a door with a number divisible by 5?

Answer 1

Numbers divisible by 5 between 1 and 20 are 5, 10, 15, 20 — 4 doors.
Probability = 4/20 = 1/5 = 0.20 = 20%.