Euclidean Algorithm - GCD Word Problem 
An Oil company has a contract to deliver 100000 litres of gasoline. Their tankers can carry 2400 litres and they can attach on trailer carrying 2200 litres to each tanker. All the tankers and trailers must be completely full on this contract, otherwise the gas would slosh around too much when going over some rough roads. Find the least number of tankers required to fulfill the contract [ each trailer, if used, must be pulled by a full tanker.]

Alright, so i know i can solve this by the Euclidean Algorithm.
Where 
 100000 = 2200x + 4600y
 But, how do i solve with the variables there.

Step 1. Divide everything through by $\gcd(2200,4600)$. (If that greatest common divisor doesn't divide 100000, then there's no solution - do you see why?) In this case, we get $500 = 11x + 23y$.
Step 2. With the remaining coefficients, use the extended Euclidean algorithm to find integers $m$ and $n$ such that $11m + 23n = 1$. Then $11(500m) + 23(500n) = 500$.
Step 3. One of the integers $500m$ and $500n$ is negative. However, you can add/subtract $23$ to/from $500m$ while subtracting/adding $11$ from/to $500n$ - it will remain a solution to $500 = 11x + 23y$. Keep doing that until both variables are positive. In this way you can even find all solutions (I find 21 solutions).
PS: To me it seems that the problem leads to the equation $100000 = 2400x+4600y$, rather than $2200x$.
