Answer:
78
Step-by-step explanation:
You take the original total: 60, and multiply it by 30 to get 1,800. You then divide 1,800 by 100 to get 18. 18 is your 30%. Now, you add the 30% to 60 getting your total number of ducks: 78.
The equation version:

It is just proportions.
The probability of selecting two red marbles would be 1/19
Answer: Choice A) Add 3.8 to both sides of the equation
Explanation:
If we knew the value of w, then we would replace it and apply PEMDAS.
However, we don't know the value of w, so we undo each step of PEMDAS going backwards.
We start with the "S" of PEMDAS, and undo the subtraction. To undo subtraction, you apply addition. To undo that "minus 3.8" we add 3.8 to both sides.
Ok, MissWalker! Please try your best to understand this, it may get confusing.
I have solved this on a different website, and here is my solving in a picture. I hope I helped!!! :D