What is the contrapositive of if a, then b? a.) if b, then a b.) if a, then not b c.) if not b, then not a d.) if not a, then not b

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