Mathematics of inverted water bottle problem
0.9L 1.2 *(∏* R2 * 15/(∏* R2 * 15+∏* R2 * 5))= 1.2 * 0.75。 The volume of this accessory is ∏ * r 2 * 5. When the volume of the whole bottle is ∏ * r 2 * 15+∏ * r 2 * 5 = ∏ * r 2 * 20 square, the height of water is 15 cm.