A fruit seller had 60 kg of pears which he graded into 3 sizes A, B and C. The ratio of the mass of Grade A pears to the mass of Grade B pears to the mass of Grade C pears was 2 : 5 : 3. There were 7 Grade B pears per kilogram. This was 2 pears more than in one kilogram of Grade A pears and 3 pears less than in one kilogram of Grade C pears. What was the ratio of the number of Grade A pears to the number of Grade B pears to the number of Grade C pears?
A/B ==2/5,
B/C ==5/3,
A+B+C==60, solve for A, B, C
A==12 kg, B==30 kg, C==18 kg
Grade B==7/kg
Grade A==7/kg - 2==5/kg
Grade C==7/kg + 3==10/kg
B==7/kg x 30 kg==210 - Grade B pears
A==5/kg x 12 kg ==60 - Grade A pears
C==10/kg x 18 kg==180 Grade C pears
So: A : B : C ==60 : 210: 180==2 : 7 : 6 [Their ratio by the number of pears in all 3 grades]