okay well question 3 is all about the units. so what helped me figure it out was to look at the info the question is giving, and make it into a legend of sorts. ie : [Q] = L^3/T and [L] = L and [R] = L stuff like that.
then what you want to do is plug all the values u wrote in your legend into the equation given. for values such as pi and 8 u can ignore those because they dont have units.
now with your equation of units, start eliminating what u can. remeber that your trying to solve for n. rearange the question untill u have L as a base on both sides of the equals sign, using logs, eliminate the Ls where you will eventually get n=3+1 and then your done. im sorry if it didnt make too much sense, im not an expert with this stuff myself.
hope it helps
