create a situation that can be modelled by this linear system, then write a related problem.
10x + 5y = 850
x - y = 10
Items of type A cost $10 each.
Items of type B cost $5 each.
The total amount spent is $850.
Ten more items of type A are bought than B.
x type A items and y type A items are bought.
Solve for x and y