Add and simplify the answer 5/8+1/8

I'm confused on this could anyone me and show me what i need to do to solve it.

32a³b² 8ab² simplify the following expression.

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