1. 2a = 3b = 0,5c = 1/3d b = 2a/3 c = 4a d = 6a
a+b+c+d = 7
a+2a/3 +4a + 6a =7 11a + 2a/3 = 7 35a = 7·3 a = 3/5 b =2/5 c= 12/5 d=18/5
2. d = V1·t1 = V2·t2 t2 = V1t1/V2 = 2·40/60 = 4/3 ore = 1ora 20 minute·
3. x/0,25 = 3y = 2z 4x = 3y = 2z y = 4x/3 z = 2x
x·4x/3 + 4x/3·2x + 2x·x = 54
4x² /3 + 8x² /3 + 2x² = 54 4x² + 2x² = 54 x² = 9 x = 3 y = 4 z = 6