The figure shows the amount of water in two rectangular tanks, L and M, at first. Ben poured ¹₄ of the water from L into M to fill it to the top, without overflowing.

1. How much water was there in Tank L at first?
2. Ben then poured all the water from Tank M into Tank L. 2790 cm³ of water overflowed from Tank L. What was the height of Tank L?

(a)
Volume of water to fill Tank M
= 18 x 15 x 15
= 4050 cm<sup>3

1</sup>₄ of volume of water in Tank L at first = 4050 cm^3  
4₄ of volume of water in Tank L at first = 4 x 4050 = 16200 cm³

Volume of water in Tank L at first = 16200 cm³

Volume of water in Tank M at first
= 18 x 15 x 17
= 4590 cm³

Total volume of water in Tank L and Tank M 
= 16200 + 4590
= 20790 cm³

Final volume of water in Tank L after 2790 cm³ of water overflowed
= 20790 - 2790
= 18000 cm³

Base area of Tank L
= 20 x 18
= 360 cm²

Height of Tank L
= 18000 ÷ 360 
= 50 cm

Answer(s): (a) 16200 cm² ; (b) 50 cm