Cycle paths inc, makes bicycles, tricycles, and unicycles. last week they made 88 more bicycles than unicycles, and 5 times as many tricycles as unicycles. if they made 40 more bicycles than tricycles, how many unicycles did they make

Let's name variables:
 x = bicycles
 y = tricycles
 z = unicycles
 We write the following system of equations:
 x = 88 + z
 y = 5z
 x = 40 + y
 We solve the equation system for z:
 1) x = 40 + y
 2) y = 5z
 3) x = 88 + z
 Substituting x and y in equation 1:
 88 + z = 40 + 5z
 We cleared z:
 4z = 88-40
 z = 48/4
 z = 12
 
 They did make 12 unicycles