Container Q and R are identical containers with the same base area and height. Container Q is filled to the brim with water while Container R is empty. After 280 cm³ of water from Container Q is poured into Container R, the depth of water in Container R is ¹₈ the depth of water in Container Q. If the height of Container R is 30 cm, what is the base area of Container R?
The depth of water is proportional to the volume of water.

After water from Container Q is poured into Container R:

Volume of water in Container Q : Volume of water in Container R
 8 : 1

1 u = 280

Total volume of Container R
= 8 u + 1 u
= 9 u
= 9 x 280
= 2520 cm³

Base area of Container R
= 2520 ÷ 30
= 84 cm²

Answer(s): 84 cm²