Answer:
By a quick online search, i found two tape diagrams:
13) You: -
Friend: - -
So you have one block, and your friend has two.
We know that you work for 3 hours, this means that your only block must represent 3 hours.
And all the blocks represent the same amount of time, then each one of the two blocks of your friend also represents 3 hours.
Then in total, he tutored for 3 hours + 3 hours = 6 hours.
14) You: -
Friend: - - - - -
In this case, you still have only one block, but now your friend has 5.
Using the same reasoning as above, we can conclude that each block represents 3 hours, and your friend has 5 of them, this means that he tutored for:
5*3 hours = 15 hours
