Question 103297
Let x=the no. of bicycles
    y=no.of tricycles
    z=no. of unicycles

(1)x=z+88
(2)y=5z
(3)x=y+40
Substituting (1) and (2) to (3),

z+88=5z+40
  88=4z+40
  48=4z
   z=12

Therefore, they made 12 unicycles!
HyperBrain