A cistern of capacity 8000 litres has external dimensions 3.3 m × 2.6 m × 1.1 m. Its side walls are 5 cm thick. What is the thickness of the bottom (assume the top is open)?

Problem Restatement

Determine the bottom thickness using capacity (internal volume) and external dimensions with known wall thickness.

Given data

• Capacity = 8000 L = 8 m^3
• External L × B × H = 3.3 m × 2.6 m × 1.1 m
• Side wall thickness = 5 cm = 0.05 m
• Bottom thickness = x m (unknown)

Concept / Setup

Internal dimensions: L_i = 3.3 − 2(0.05) = 3.2 m; B_i = 2.6 − 2(0.05) = 2.5 m; H_i = 1.1 − x (top open)

Step-by-step calculation

Internal volume = L_iB_iH_i = 3.2 × 2.5 × (1.1 − x)8 = 8.0 × (1.1 − x) → 1.1 − x = 1.0 → x = 0.1 m = 10 cm

Final Answer

Bottom thickness = 10 cm.