2015 · Q52
A hollow cylindrical drum has internal diameter of 30 cm and a height of 1 m. What is the maximum number of cylindrical boxes of diameter 10 cm and height 10 cm each that can be packed in the drum?
Elementary MathematicsMensuration
- A60
- B70
- C80
- D90
Explanation
There are 10 layers of 10 cm; each layer fits 7 circles of diameter 10 cm in a 30 cm circle (1 in the centre, 6 around), giving 70 boxes. Hence option (b).