Answer: 1 ⁸/₂₁ litres
Explanation:
First find a common multiple to enable you add them up:
= 21
21 will be the denominator.
Multiply each numerator by the number you get when you divide 21 by the denominator.
= 21/3 = 7
= 7 * 2 = 14
= 21/7 = 3
= 3 * 5
= 15
![= (14 + 15)/(21) \\\\= (29)/(21)](https://img.qammunity.org/2022/formulas/mathematics/high-school/81802v6gbyfxc6dzjwez2gmdfa0rw4cxj0.png)
litres