Asandwich shop has 30 stores and 60% of the stores are in california the rest of the stores are in nevada how many stores are in california and how many are in nevada

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