Acertain grey paint calls for 3 parts black and 15 parts white. how many gallons of black are needed for 40 gallons of grey?

Ijust need to see how to do this. so you don’t have to answer all of them just a step by step explanation of one.

Over the last 8 nights, elyse earned the following in tips: {105, 120, 84, 95, 100, 132, 140}. if she earns $140 a night for the next four nights, which measure of center would increase more, the mean or median?

If 2(a^2+b^2)=(a+b)^2 then, > a+b=0, > ab=0, > a=b, > 2a=b