Question 33142
First try to form equations, with the informations given in the question.
let U be unicycles,B be bicycles and T be tricycles.
then,
  eq 1.  B =  88 + U

  eq 2.   T =  5 * U
   
   eq 3.  B =  40 + T  (GIVEN )
 
compare eq 1 & eq 2,we get 

       88 + U = 40 + T

NOW FROM eq 2. , substitute T = 5*U, we get

88 + U = 40 + (5 * U)

88  - 40 = 5U - U
48 = 4U

Therefore U = 12.SO THE NUMBER OF UNICYCLES IS 12.

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