The bill for five glasses of apple juice and four salads is 9.50$ but the bill for four glasses of apple juice and five salads is 10.50$. what would the bill for one glass of apple juice and one salad be?

Problem number 26 of the rhind papyrus says: find a quantity such that when it is added to of itself the result is a 15. the modern day equation that models this problem is x + x = 15. what is the solution to the equation? x = 10 x = 12 x = 15 x = 30