Well what I would do first is to divide 128 by 32 which I do believe gets you 4. So now you know that 1 cup of powder can make 4 servings. So you now know that each serving only requires 1/4 cup of the powder.
So now we know Jeff went over so now we have Jeff added 2/3 and he only needs 1/4. I would now make them both equivalent by multiplying the numerator and denominator of 2/3 by 4 and the same for 1/4 but instead by 4 multiply it by 3 which you would get 2/3=8/12 and 1/4=3/12. Now subtract the two to get your answer.
8/12-3/12=5/12
Answer: He went over and he needs to remove 5/12 of the cup
8 as you round up 405 to 400 and divide by 50 and get 8
Answer: (x,y) = (1,6)
Step-by-step explanation:
I'm going to put it into decimals because it is easier.
3.5*1.5=5.25 or

Hope that helps