Question

I'm really stuck on this question and if anyone could help me with it I'd be so grateful

Answer 1

150

Explanation:

Rate at which volume decrease:

(1 × 2 × 20/100) ÷ 30

= 1/75 m³/min

Total volume:

½ × (1.4 + 0.6) × 2 × 1

= 2 m³

Time = 2 ÷ 1/75

= 150 mins