How many quarts of a 50% solution of acid must be added to 20 quarts of a 20% solution of acid to obtain a mixture containing a 40% solution of acid?

Turner's mom measured his room to see how long the wallpaper border needed to be. if two walls are 15 feet long and two walls are 12 feet long, how long should the strip of border be cut?

Which fraction is not equivalent to 8/12 a. 2/3 b. 24/36 c. 4/10 d. 6/10

Me because some of question i don’t understand