bob is painting a new mural on the wall of his school. He will need 20 gallons of paint that are 33% oil. The paint store sells paint that is 25% oil and 35% oil. How many gallons of each should he buy?

Pls! does anybody know a shortcut for answering these types of questions in the future?

Factor k2 - 17k + 16. a.(k - 2)(k - 8) b.(k - 1)(k + 16) c.(k - 1)(k - 16)

Sanya noticed that the temperature was falling at a steady rate of 1.4 degrees every hour from the time that she first checked her outdoor thermometer. by 6 a.m., the temperature had fallen 21 degrees. which expression can you use to find how many hours earlier she had first checked the thermometer?