a) 40 = 5/6
40 : 5 * 6 = 48
48 : 6 = 8 cu Vivaldi
48 = 2/3
48 : 2 * 3 = 72
72 : 3 = 24 cu vioara
40 + 8 + 24 = 72 magneti vanduti
b) 24 * 5 = 120€ suma maxima
24 : 3 = 8 magneti
8 * 10 = 80€ uma minima
c) 3/5...........3 g
2/5............x
x = 3 * 2/5 : 3/5
x = 6/5 * 5/3
x = 2 g pierderi