Acrane can pick up 3.0 tons of excavated earth in one hour. the crane operator's wages are $15 per hour. what, then, is the cost of picking up 85 kg of excavated earth?

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