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

1. How much water was there in Tank B at first?
2. Rael then poured all the water from Tank C into Tank B. 8640 cm³ of water overflowed from Tank B. What was the height of Tank B?

(a)
Volume of water to fill Tank C
= 20 x 16 x 17
= 5440 cm<sup>3

1</sup>₄ of volume of water in Tank B at first = 5440 cm^3  
4₄ of volume of water in Tank B at first = 4 x 5440 = 21760 cm³

Volume of water in Tank B at first = 21760 cm³

Volume of water in Tank C at first
= 20 x 16 x 19
= 6080 cm³

Total volume of water in Tank B and Tank C 
= 21760 + 6080
= 27840 cm³

Final volume of water in Tank B after 8640 cm³ of water overflowed
= 27840 - 8640
= 19200 cm³

Base area of Tank B
= 24 x 20
= 480 cm²

Height of Tank B
= 19200 ÷ 480 
= 40 cm

Answer(s): (a) 21760 cm² ; (b) 40 cm