Word Problems with Percents

All word problems that involve percents require you to do one of three basic things.

1. Find the percent of a number

e.g. What is 25% of 44?

2. Find what a number is when you are given a percent of it

e.g. 18 is 35% of what number?

3. Find what percent a number is of another number

e.g. 40 is what percent of 95?

The way to set all of these problems up is to write two fractions. The fraction on the left side has the part of the whole (not the percent) as the numerator, and the amount of the whole as the denominator. The fraction on the right side has the percent as the numerator and 100 as the denominator. The value you don’t know and are solving for can be represented by x.

When you set up the example question for the first type of question above it will look like:

The example for number two:

Number three:

Now you cross multiply and solve for x.

For example the way you would do number one is:

So 25% of 44 is 11.

Multistep Problems

Many times you will have to do a calculation unrelated to percentage before you do the calculation related to percent in order to arrive at the correct answer. It won’t be very complicated, but you need to pay attention to the wording of the question.

Here’s an example question:

A trip from City A to City B costs $75 in gas and tolls. The toll fees add up to $4.50. The gas for a trip from City B to City C costs 30% more, but there are no tolls. How much will the gas cost for a trip from City B to City C?

Of course when you answer the question the first thing you should do is the precalculation of removing the toll cost. This will enable you to arrive at the correct answer since there are no tolls in the second trip.

multi-step-correction-2

The cost of gas for a trip from City B to City C is $91.65  .

Percent Change

If a question on the GED math test asks you to find a percent change (the percentage something increases or decreases by), all you need to do is divide the amount of change by the original amount.

Example question:

Your new apartment is 900 square feet and your old apartment was 750 square feet. How much larger is your new apartment percentage-wise?

First you find the difference:

Then you divide the difference amount by the original amount:

Then all you need to do is convert the result of the division to a percent:

.2 = 20%

 

 

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23 comments

  1. Sarah Dessen fan says:

    Man, the math section of the GED is so complicated. I wish there was no need for the math portion, then I’d. Already have my GED. The math part is the last test I need to take yet the subject I struggle the most with. I can only pray I pass.

    • C-Los Pugh says:

      I feel the same way math is my only and last subject I have left to take i’m taking it again tomorrow so like u said I pray I pass it this time. This will be my third time I have to pass it because I wont to get me GED before the new 2014 one I refuse to take the new one it will be harder an much longer. So good luck an i’ll pray for u too. Just don’t give up!!!

  2. Christopher Colangelo says:

    Your so right it is very complicated but you still have to pass that part in order to receive your GED. I see this site is very helpful Im sure with the help of this site, you’ll do better next time. Good Luck to you and I will be retesting the math part next month i only need 20 points to pass.

  3. Tara says:

    For the example question on Multistep Problems, there seems to be a typo because the answer is incorrect.
    70.05 + 21.15 =91.20 Not 91.65

  4. Teresa Marks says:

    okay I am confused with the percent of change problem (The problem is 950 and 700) why did you change the 950 to 900.Please explain because I am lost I know how to do the percent decrease and increase

  5. robert says:

    i was wondering why the answer to the 750 divided by one fifty is .2 cause none of the numbers go into anyy of the 150 i got zero please explain futher
    -appreaciated-

    • Ziyi says:

      Well, it’s 150 divided by 750. You’re right that 750 doesn’t fit into 150 but part of 750 does, that’s where the .2 comes from. It just means that .2 or 20% of 750 fits into 150.

  6. Ray says:

    The answer for multistep is 91.65 since you’re supposed 70.50 to 21.15
    You used 70.50 to multiply it by .30 that’s how you got 21.15 in the first place so why did you move the decimal and lower the value to 70.05?

  7. Megan Trotter says:

    I take my math test on the 28th of this mounth I am Getting a little nervous I have my fingers crossed that I cn pass This site has hepled me understand so much more then I did I didn’t even know how to divide I few months ago, but you have made it so esay. Thank you I hope I pass and when i will let you know 🙂

  8. nanzina says:

    Hi thank you for your help! is there an easier way on how to pass the calculator part of the test, what will be on the test as far as the calculator part. thanks again and blesings to you ziyi.

  9. Catresha says:

    Got 10 points higher on the mathematics section of the GED test today. Was fairly easy,but did,nt have enough time to read. Taking it again next week 🙂 ! I,m gonna stay confident as always,& keep on studying :)!

    • Ziyi says:

      Right, good luck. Now at least you have a clearer idea of what to focus on. Will pass next time for sure!

      • Catresha says:

        Thanks 🙂 410 is the passing score in my state, I have 390 ,but all other scores are high,& all I need is410. So I have the batteryscore already,&410 will take me way over my overall score :)!

  10. jaz says:

    really helped me rembered cross multiplying usefull 🙂

  11. kay thomas says:

    I hate maths.all that algebra on the ged is really not necessary in life. whenever you can count your money and hours worked that’s it. leave that all that complicated maths for engineers and scientist.had to write the ged maths five times .

  12. maria alvarez says:

    how do you get the 2 in the divison part 750 divided by 150

  13. ismail says:

    Hi there…how do you get 750÷150 =2
    Isnt 750÷150=5

  14. Jim says:

    Wouldn’t it be easier just to do this on the calculator since you can use it on your whole math portion of the GED now?

    Problem 1 you just enter 0.25 x 44 and get 11
    Problem 2 you just enter 18 divided by 35% and you get 51.428571
    Problem 3 you just enter 40 divided by 95 and you get 0.421

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