You might have had to read this problem over several times before you understood it clearly - it wasn't easy! However, we have received many correct solutions and the majority of you tackled it in the same way. Esther explains how she went about solving the problem very well:The answer is 8 litres.
Esther also wrote:
Excellent reasoning Esther, thank you. Pupils from Queens College Junior School used a similar method to the first way Esther described. Greg, Liam, George and Joe from Moorfield Junior School found a slightly different way:
Alex from Columbia Independent School, MO, USA worked at the problem in a similar way to Esther's second method:
Finally, pupils from Wilby School tackled the problem in a slightly different way again. Here is Georgina's solution:
Thank you very much to all those who sent solutions - even if there isn't room here to mention you personally.