It costs $0.0015 to leave a lightbulb on for an hour. How much would it cost to have a lightbulb on for a month? (Helpful conversions: There are 24 hours
in a day, and there are 30 days in a month).

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