A farmer plants the same amount every day, adding up to 2 1/2 acres at the end of the year. if the year is 2/3 over, how many acres has the farmer planted?

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