German silver is a mixture of copper, nickel and zinc.
of the total mass is copper and 
of the remainder
is nickel. What mass of German silver will contain 
kg of zinc?
A
B
C68 kg
D
Solution given by you is incorrect:You have given:Let the total mass = xMass of copper = 3/4 xRemaining mass = x - 3/4 x = 1/4 xMass of nickel = 3/8 (1/4 x) = 3/32 xHence, mass of zinc = x - (1/4 x) - (3/32 x) = (32x - 8x - 3x)/32 = 21 x /32Whereas mass of zinc = x - (3/4 x) - (3/32 x) , since Mass of copper = 3/4 x