The figure shows the amount of water in two rectangular tanks, Q and R, at first. Elijah poured ¹₅ of the water from Q into R to fill it to the top, without overflowing.

1. How much water was there in Tank Q at first?
2. Elijah then poured all the water from Tank R into Tank Q. 5292 cm³ of water overflowed from Tank Q. What was the height of Tank Q?

(a)
Volume of water to fill Tank R
= 18 x 14 x 13
= 3276 cm<sup>3

1</sup>₅ of volume of water in Tank Q at first = 3276 cm^3  
5₅ of volume of water in Tank Q at first = 5 x 3276 = 16380 cm³

Volume of water in Tank Q at first = 16380 cm³

Volume of water in Tank R at first
= 18 x 14 x 16
= 4032 cm³

Total volume of water in Tank Q and Tank R 
= 16380 + 4032
= 20412 cm³

Final volume of water in Tank Q after 5292 cm³ of water overflowed
= 20412 - 5292
= 15120 cm³

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

Height of Tank Q
= 15120 ÷ 360 
= 42 cm

Answer(s): (a) 16380 cm² ; (b) 42 cm