Xiao Zhang and Xiao Wang have to process the same number of parts, using the old machine tool to process 20 pieces per hour. Later, the factory gave them a new machine tool and processed 60 pieces per

Xiao Zhang and Xiao Wang have to process the same number of parts, using the old machine tool to process 20 pieces per hour. Later, the factory gave them a new machine tool and processed 60 pieces per hour. Let Xiao Wang take 3t: 2t,

So the total number of parts is: 20×3t+60×2t= 180t (pieces),

Parts made by Xiao Zhang: old machine tool180t× 2 5 = 72t, new machine tool180t× 3 5 =108t.

Xiao Zhang's time: 72t÷20+ 108t÷60= 27 5 t,

Time difference between them: 27 5 t -(3t+2t)= 18 60, t= 3 4,

Therefore, the total number of parts: 20× 3t+60× 2t =180t =180× 34 =135 (pieces);

A: They each completed 135 parts.