Hi Eloise,
These questions are really awful because they can be interpreted in different ways.
Your interpretation of the first one sound ok. Although, there is no reason to think that he does work 7 days a week. Mind you, he is working VERY long hours. Also 69/7=9.857.... which is closer to 9.9 then it is to your 9.8hours.
The second one is also very badly worded. We do not know if it is 1/5 before the tax is taken out of afterwards.
But again, your interpretation is reasonable and the maths you have done appears to be corrrect:)
The last one looks reasonable too :))