Kelly joins powerhouse gym. the cost is $30 per month and a one-time $100 joining fee. lisa joins megamuscle gym for $35 per month and a $50 joining fee. in how many months will lisa have paid more than kelly?

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