49 is 35% of what number

400% of what number is 150

If you can read a 120 page book in 4 hours, how long will it take to read 150 pages

Did you do any in class? Is there an example that's been completely worked on in your textbook or in your notes?

Do you know how to change 35% to a decimal?

What number is 120% of 16

No I have such a hard time with algebra

One thing that's really helpful when doing word problems is learning how to "decode" plain English into math.

Here's a "decoder ring" to help you decipher what each problem is asking and write it out as an equation. There are only four things in the list:

(1) The phrase "what number" means "x". In other words, it's the value you need to solve for.
(2) The word "is" generally translates into "=".
(3) The word "of" usually means to multiply (in other words, it means "times").
(4) The symbol "%" means you should divide the number by 100 and drop the % symbol.

That's pretty much all you need to know to translate each of your word problems into algebraic equations.

Let's do your original question as an example. "49 is 35% of what number?"

Now let's translate it step by step. I'll show the translation in parentheses:

49 (there's nothing to translate here; it just means 49 of course) is (=) 35% (35/100) of (times) what number(x)?

Now let's write it just with math:

49=\frac{35}{100}x

That's it. Now all you have to do is solve for x. Do you know how to do that?

Let's do one more example just to drive the point home.
"What number is 120% of 16?"

What number (x) is (=) 120% (120/100) of (times) 16?

x=\(\frac{120}{100}\)\(16\)

This time you don't even have to solve for x; it's already done. Just do the multiplication and division, and you have your answer.

Does any of that make sense?

Also, here's a quick primer on converting from % into decimal.

As I said above, the "%" symbol literally means "out of 100" or "divided by 100", so all you really need to do when you encounter it is divide the preceding number by 100. There's no need to use a calculate or do any long division or anything complicated like that. Dividing by 100 is as simple as moving the decimal place over two places to the left.

Here are some examples:
39.2% = .392
400% = 4.00
0.76% = .0076
1.9% = .019
1312% = 13.12

So in the problems above, instead of replacing 35% with 35/100, for example, you could also have used .35 instead. Either way is correct, and you should end up with the same answer once you solve for x.