Byron S. answered 10/07/14
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Math and Science Tutor with an Engineering Background
Lets look at how many of each thing each type of cycle needs.
A bicycle has 1 front handlebar, 1 seat, and 2 wheels.
A tandem has 1 front handlebar, 2 seats, and 2 wheels.
A tricycle has 1 front handlebar, 1 seat, and 3 wheels.
Let x be the number of bicycles,
let y be the number of tandems,
and let z be the number of tricycles.
They all require 1 front handlebar, so with 118 front handlebars, there are a total of 118 cycles.
x+y+z=118
The tandem is the only cycle to require more than one seat, so since there are 135-118=17 extra seats, that means there are y=17 tandem bicycles.
Finally, we can add up the number of wheels needed:
2x+2y+3z=269
We have two equations, with two unknowns (we know y=17):
x+y+z=118
2x+2y+3z=269
After substituting in y and simplifying, you can solve for x and z using your favorite method for solving a system of two equations.
Please comment if you need more help.