Harry potter maths

For the last 2 days my homeroom has been working on this harry potter sheet we need to write down question 1,2,3,4 next to bus a,bus b and bus c then we looked at the questions and for example it would say " how long does it take to get from herbology to hagrids hut " and we would have to write under bus A what the asnwer is for bus A then for b and then c. The lines on the sheet in 1 collum is saying that the bus doesn't stop there so It keeps on going untill the next time.

I found it hard to understand what the - is on the sheet
I found it easy to do everything except understand the -
Here are some photos of my sheet.