PSLE
Rachel has two types of bottles, large and small. She filled 3 large bottles and 7 small bottles with 13.1 ℓ of the milk she has. With the remaining milk, she could not fill another large bottle as she was short of 0.3 ℓ. Thus, she filled another small bottle and had 0.6 ℓ left over.

1. How many litres of milk did a large bottle hold more than a small bottle?
2. How many litres of milk did a small bottle hold?

(a)
Difference between the capacity of the small bottle and the large bottle
= 0.6 + 0.3 
= 0.9 ℓ

(b)
Volume of 1 small bottle = 1 u
Volume of 7 small bottles = 7 u

Volume of 1 large bottle = 1 u + 0.9
Volume of 3 large bottles = 3(1 u + 0.9) = 3 u + 2.7 

Total volume of 7 small bottles and 3 large bottles
= 3 u + 2.7 + 7 u
= 10 u + 2.7

10 u + 2.7 = 13.1
10 u = 13.1 - 2.7 
10 u = 10.4

1 u = 10.4 ÷ 10 = 1.04

Volume of a small bottle 
= 1 u
= 1.04 ℓ

Answer(s): (a) 0.9 ℓ; (b) 1.04 ℓ