Just had a crack at Q1 using a different method to YS by calculating turning moments about the datum:
Firstly I calculate the fuel weight to be 100Kg (140 x 0.714).
LEMAC is at 2.5m from datum.
Turning moment for pilot & passenger = 160Kg x 2.5m = 400Kgm
Turning moment for the basic mass + fuel at same arm = 1300Kg x 3m =3900Kgm
Total moment = 3900Kgm + 400Kgm = 4300Kgm
Total weight = 1200kg(basic) + 100Kg(fuel) + 160Kg(pilot & PAX) = 1460Kg
CG position = 4300Kgm/1460Kg = 2.945m from datum, which is 0.445m from LEMAC, which is 22.25% MAC. Close enough to answer c.
Slightly long winded, but another way to get there.
Noz