The answer is:
B
First, look for some of the key words in the word problem.
Plus, is the same as the...
Now we can use those key words and translate it into an equation.
You don't know the price of 3 notebooks, so you should put: 3x
Instead of saying plus, we can say: +
It says "...3 notebooks plus a $30 backpack..." so we add 30.
Instead of saying "is the same as the", we can say: =
You don't know the price of 11 notebooks either, so you should put: 11x
Now, put together the equation:
3x + 30 = 11x
There is your equation! Match it up with one of the given answers and you will receive B.
