Question

Kevin sold 2 unicycles and 1 bicycle for a total of $110. Greg sold 4 unicycles and 3 bicycles for a total cost of $268. What is the cost of 1 bicycle?

Answer 1

Simultaneous Equations

2u +   b = $110
4u + 3b = $268

(x2) 4u + 2b = $220
(x1) 4u + 3b = $268

<em />If both the matching coefficients are the same, we subtract equation 2 from equation 1

2b - 3b = -b
$220 - $268 = $-48
-b = -$48
b = $48

If you want to find out what a unicycle costs...
Substitute b = $48 into the first equation
2u + $48 = $110
Balance the equation, whatever happens on one side, happens on the other.
2u + $48 (-$48) = $110 (-$48)
2u = $62
2u(/2) = $62(/2)
u = $31