Take off for a minute 10 clamps of type C. Then the rest amount of clamps C will be exactly equal to sum of types A and B, and altogether (C-10), A and B will comprise 300 clamps. Hence, C = 150 + 10, while A + B = 150. We also are given that the number of clamps of the type B is twice as many as that of type A. Hence, we just get the Answer. A = 50, B = 100 and C = 160.