Temperatures across four days — Averages Aptitude Question
Temperatures across four days: The average temperature for Monday, Tuesday and Wednesday was 37°, and for Tuesday,… Answer and worked solution on CodeKairo.
- Topic: Averages
- Section: Quantitative Aptitude
- Difficulty: Hard
- Time target: 135 seconds
Question
The average temperature for Monday, Tuesday and Wednesday was 37°, and for Tuesday, Wednesday and Thursday it was 34°. If Thursday's temperature was 4/5 of Monday's, what was Monday's temperature?
Options
- 36°
- 38°
- 40°
- 45°
Show the answer and the worked solution
Correct answer: D. 45°
Worked solution
- Mon + Tue + Wed = 3 × 37 = 111.
- Tue + Wed + Thu = 3 × 34 = 102.
- Subtracting: Mon − Thu = 9.
- Thu = (4/5)Mon, so Mon − 0.8Mon = 9 → 0.2Mon = 9 → Mon = 45°.
Answer: 45°.
The idea
Overlapping windows: subtract the two totals so the shared days cancel and only the two end days remain. Then use the given relation between them.
Shortcut. The two totals differ by 3 × (37 − 34) = 9, which is Monday − Thursday = Monday ÷ 5, so Monday = 45°.
Common trap. "36°" — solving correctly but reporting Thursday's temperature (4/5 × 45) instead of Monday's.