2025 PHS PRELIMS P1 Q22

Box X contains balls numbered 1, 2, 3 and 4. Box Y contains balls numbered 1, 3, 5 and 6. May draws one ball at random from each box and adds the numbers.

1. Complete the possibility diagram.[2]

   \(X + Y\)	\(1\)	\(3\)	\(5\)	\(6\)
   \(1\)	\(2\)			\(7\)
   \(2\)		\(5\)
   \(3\)			\(8\)
   \(4\)		\(7\)		\(10\)

2. Find the probability that the sum is 6.[1]
3. Box Z contains balls numbered 10, 20, 30 and 40. Albert draws one ball from each of X, Y and Z. Find the probability that their sum is more than 30 but less than 36.[2]