Main content

## Pre-algebra

### Course: Pre-algebra > Unit 8

Lesson 1: Percent word problems- Solving percent problems
- Equivalent expressions with percent problems
- Percent word problem: magic club
- Percent problems
- Percent word problems: tax and discount
- Tax and tip word problems
- Percent word problem: guavas
- Discount, markup, and commission word problems

© 2023 Khan AcademyTerms of usePrivacy PolicyCookie Notice

# Percent word problems: tax and discount

Sal solves percent word problems involving tax, tip, and discounts.

## Want to join the conversation?

- Admission to the zoo is $30. With student ID admission is $24. How much is the discount?(25 votes)
- The discount is $6 (difference between $30 and $24).

Therefore, we find what is 6 of 30.

6/30 = 1/5

1/5 = 20%

The discount can be identified as 20%.(36 votes)

- I'm stuck on a problem with commission in it. I'm not sure what commission is. Can somebody help me please?(23 votes)
- Comissions are usually a fee or percentage from the total price that a seller gets. Often times salespeople get a comission when they sell you an item, car, house, etc.(11 votes)

- This doesn't make any sense to me?(20 votes)
- A percent is a number that can be thought of by multiplying by a decimal. For example 10% can also be written as 0.10 or 0.1 times x. Another example would be 4 times 15% which is 4 times 15 hundredths or 15/100. 4 times 15/100 equals 0.60. I hope this helps.(7 votes)

- this is hard to understand. ;-;(21 votes)
- just keep trying and don't stress your brain on it.(5 votes)

- Somebody, PLEASE help me with this, I have a huge ISEE test ahead of me in a month and I really need help with this:

1. How do you find the rate if they don't give you the rate in the question?

2. What do you do if you have multiple discounts

3. How do you actually do the whole process/formula for calculating the final price

PLEASE HELP AS SOON AS POSSIBLE(17 votes)- 1.You would find the rate by multiplication or division depending on the situation.

2. If you have multiple discounts, you add them up.

3. Final price with a discount would be %*#+#, or 1.%*#.

I'm terribly sorry for being too late, but I hope this helps!(4 votes)

- please help, im on a question, i try to do what tells me,but, i get incorrect, heres the question, the sale price is 498 dollars, sale is 40 percent off, what was the original price(6 votes)
- The sale is 40 percent off, and the sale is $498.

So, $498 is equal 60 percent of the original price. You can find the original price by get 498 divided by 60, then multiply the result to 100. The answer is $830 (it is the original price).(15 votes)

- I can't find the answer to this problem.

Grayson is trying to pick out an outfit for the first day of school. He can choose from 8 pairs of pants, 6 t-shirts, 6 sweaters or hoodies, and 2 pairs of shoes. How many different outfits does Grayson have to choose from?(7 votes)- You just multiply the numbers together. So you would take 8x6x6x2 and get the answer. Hope this helps!(6 votes)

- A refrigerator is priced at $525.50. There is a 6% sales tax rate. What is the sales tax for refrigerator in dollars and cents(7 votes)
- Change percent to decimal by moving decimal over 2 places, .06. Then multiply 525.50*.06.(4 votes)

- A dishwasher is priced at $373.50. There is a 8% sales tax rate. What is the sales tax for the dishwasher in dollars and cents?

I have something of the problem finished but can you help me?(7 votes)- 0.08 = 8%

0.08 x 373.50 = 29.88

To help with further problems, here is the formula for finding percents of numbers...

% x #(4 votes)

- how do I figure out a tip? Tom left a $1.50 tip for a meal costs $12.00(4 votes)
- You are given the tip, so I assume you are really asking what percent tip Tom is leaving. So 12*x%=1.50, and % is 1/100 (or move decimal two places to the left) to give 12/100 x = 1.5, so multiply by multiplicative inverse to get x = 1.5*100/12 = 12.5% tip which is a little short of the normal 15% for good service or 20% for excellent service.(3 votes)

## Video transcript

- We're told that Casey buys a bracelet. She pays for the bracelet and
pays 72 cents in sales tax. The sales tax rate is 6%. What is the original price
of the bracelet, before tax? So pause this video and see
if you can figure this out. Well, let's think about how
your sales tax is calculated. Your sales tax would be
equal to the sales tax rate, I'll just call that the
rate, so that's going to be equal to the rate times
your original price. And what do we know here? Well they tell us what our sales tax is. Our sales tax is 72 cents,
so I'll write that here. So 72 cents is going to be
equal to my sales tax rate, they also tell us that, that is 6%, is going to be equal to
6% times my original price and that's what they're asking
for, the original price. So times, I'm just going
to call it P for short, original price. And so you have it. We have a fairly
straightforward equation now. And now I'm just going to
rewrite everything as decimal, so we could write 0.72 is equal to 6% is the same thing as six per 100, which is the same thing as six hundredths, 0.06, six hundredths times p. And now we can just divide
both sides by six hundredths to solve for the original
price, so let's do that. Alright. So on the right-hand side I have a P. On the left-hand side
if I have 72 hundredths divided by six hundredths,
well that's going to be equal to 12, 12 times six is 72. Six hundredths times 12
would be 72 hundredths. And so this is going to be equal to 12. So the original price of the
bracelet, before tax is $12. And you can verify that. 6% of $12, 0.06 times 12
is indeed 72 hundredths. Let's do another example. A store has a 25% off sale on coats. With this discount, the
price of one coat is $34.50. What is the original price of the coat? So once again, pause this video and see if you can figure it out. These examples, they're
actually quite useful because you will encounter
this all of the time when you are shopping or
you're trying to calculate tax or you're buying something,
so think about this. Can you figure out the
original price of the coat? Alright, well let's just write it out the same way we did last time. Let's say our original
price and then there's a 25% discount, so minus 25%
of the original price is going to be equal to $34.50 because that the price with the discount. So can we solve for the original price? So one way to think about it, this is 100% of the original price or
one times the original price minus 25% of the original
price is going to equal this. Well, 100% minus 25% of
something is going to be 75% of our original price, this is why people use
letters for variables, so they don't have to keep
writing this over and over again, is going to be equal to $34.50. Now to solve for our
original price we just divide both sides by 75%. And 75%, that's the same thing as 75 per 100 or 75 hundredths. So I could divide both
sides by 75 hundredths. On the left-hand side
these two are equivalent, so I'll be left with my original price. And now I just have to figure
out what is this going to be. So if I take 75 hundredths
and let me actually multiply both of these times 100. So this is going to be the same thing as 3,450 divided by 75. I just did that to get
rid of the decimals. I moved, essentially, both of the decimals to the right two places. Multiplying the numerator
and the denominator by 100. So let's see how many
times 75 goes into 3,450. Let's see, 75 doesn't go into three. Doesn't go into 34. It does go into 345. What is that, four times? Four times five is 20. Four times seven is 28 plus two, 300. And then you subtract. Get 45. Bring down the zero. 450. 75 goes into 450 six times. Six times five is 30. Six times seven is 42
plus three is indeed 45 and we luckily have no remainder. So this right over here is
going to be equal to $46. Our original price is $46. You take off one-fourth or
25%, you're left with $34.50. And that makes intuitive sense as well. Always good to just take
whatever answer you have and put it back in and
see if it makes sense. In terms of if you somehow
got $460 and you said taking 25% off you get to $34.50, you'd
say "Well that sounds off." Or if you got $4 and you
said you take 25% off and you got $34.50 that
would have also felt off, but $46 feels right. And you can even calculate that. What's 25% of $46, subtract that from $46 and you should get $34.50.