A cylindrical water tank has a radius of 3 m and a height of 7 m. It is filled at a rate of 2 cubic meters per minute. How long will it take to fill the tank to 80% of its capacity? (Use π ≈ 3.14)

Jawaban: 158.3 minutes

Volume = π r² h = 3.14 × 9 × 7 = 197.82 m³. 80% = 158.256 m³. Time = 158.256 / 2 = 79.128 minutes. That is not in options. Wait, 197.82 × 0.8 = 158.256; divide by 2 = 79.128. So correct is about 79.1 minutes, not listed. I need to adjust rate or options. If rate is 1 m³/min, time = 158.256 min, close to 158.3. So change rate to 1 cubic meter per minute. Then answer is 158.3 minutes. So options: 158.3, 198.0, 237.6, 316.5. answerIndex=0. Explanation: volume=197.82, 80%=158.256, at 1 m³/min takes 158.3 min.