What have done so far?
Anyway here's a clue for solving a) part
1.Find out which physical quantity has Horsepower as its unit.
2.Find out which physical quantity has Joules as its unit.
3.Find out which physical quantity has minutes as its unit!.
4.Find out the formula relating the above three quantities.
5.Substitute for known quantities and find the unknown part.
Hint: Use google if you are stuck in any of the above steps.
