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

1. How much water was there in Tank T at first?
2. Ahmad then poured all the water from Tank U into Tank T. 5040 cm³ of water overflowed from Tank T. What was the height of Tank T?

(a)
Volume of water to fill Tank U
= 15 x 13 x 15
= 2925 cm<sup>3

1</sup>₅ of volume of water in Tank T at first = 2925 cm^3  
5₅ of volume of water in Tank T at first = 5 x 2925 = 14625 cm³

Volume of water in Tank T at first = 14625 cm³

Volume of water in Tank U at first
= 15 x 13 x 17
= 3315 cm³

Total volume of water in Tank T and Tank U 
= 14625 + 3315
= 17940 cm³

Final volume of water in Tank T after 5040 cm³ of water overflowed
= 17940 - 5040
= 12900 cm³

Base area of Tank T
= 20 x 15
= 300 cm²

Height of Tank T
= 12900 ÷ 300 
= 43 cm

Answer(s): (a) 14625 cm² ; (b) 43 cm