2023 · Q85
The mean of p, q, r, s and t is 280. If the mean of p, r and t is 240, what is the mean of q and s?
Elementary MathematicsStatistics
- A310
- B320
- C330
- D340
Explanation
The sum of all five numbers is 5 × 280 = 1400, while the sum of p, r and t is 3 × 240 = 720. Hence q + s = 1400 − 720 = 680. The mean of q and s is 680/2 = 340, option (D).