In paris, the sculpture long-term, created by armand fernandez, contains 60 cars embedded in 3.5 million pounds of concrete. how many tons of concrete is this?

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