Just one advice Delta Uniform. You probly know this but it makes the questions much easier.
When calulating questions regarding time and degrees there is a function on basic calculators which makes life easier.
I have a casio fx-82MS and on the keypad it has the sign (,)
So when I calculate the first question I just type the following.
5,20,20,/0,4 and you get 80,5,0