If p, q, r and s are distinct single digit positive numbers, then what is the greatest value of (p + q)(r + s)?
A
230
B
225
C
224
D
221
Correct Answer: Option B
Explanation
1. **Analyze Constraints & Goal:** We need to find the 'greatest value' of $(p+q)(r+s)$ using 'distinct single digit positive numbers'.
2. **Greedy Selection (Boundary Condition):** To get the maximum output, we must use the maximum inputs.