Water and oil are poured into a u-shape tube, as shown below. The column of oil, on the right side, is 25 cm tall, and the distance between the top of the two columns is 9 cm. Calculate the density of the oil.

• A. 360 kg/m³
• B. 560 kg/m³
• C. 640 kg/m³
• D. 1562 kg/m³