Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ ¹ ² ³ °
 

You are not logged in. #1 20121220 04:21:46
machine probabilityThere are 4 machine and it is known that exactly 2 of them are faulty.they are tested one by one in a random order 