What is the percent Of decrease from 50 to 21

Please anwser accurate and I give brailiest

Determine which postulate or theorem can be used to prove that lmn =nmo

George writes the mixed number as sum and uses the distributive property 1/2.-2/5=1/2-2+2/5=1/2

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