Why do this problem?
involves a great deal of calculating in a context which might engage children! Learners will have to read the information carefully in order to extract the appropriate figures.
You could introduce the problem in the form of a story, perhaps by projecting it, a paragraph at a time. Having read everything through once, invite children to chat in pairs about what they might do. Take some suggestions and then perhaps read everything through again.
Allow children plenty of time to work in pairs, bringing the together to share important ideas at suitable intervals, if appopriate (a mini-plenary).
In the plenary, you could choose a few pairs to explain their thinking to everyone.
What order do you want to work things out?
What does this tell you?