A dress costs $60. It is 40% off, then 5% sales tax is added. What… Step by Step

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The question

Question: A dress costs $60.

It is 40% off, then 5% sales tax is added.

What is the final price?

1 Find the discount

Percent means out of 100.

So 40% is 40 divided by 100: 0.4.

The point moves 2 places to the left.

40% = 40 ÷ 100 = 0.4

The discount is 40% of $60.

"Of" means times: 0.4 times $60.

That is $24.

discount = 0.4 × $60 = $24

To multiply decimals: first 4 times 60, as whole numbers.

That is 240.

Then count the decimal places: 1.

So it is 24.0.

4 × 60 = 240

1 decimal places: 24.0

Careful!

We can't just take 5% from 40%.

The tax is on the sale price, not on $60.

Careful: not 40% − 5% = 35% off: $39 ✗

2 Take it off

A discount comes off the price.

$60 minus $24 is $36.

sale price = $60 − $24 = $36

3 Find the tax

Percent means out of 100.

So 5% is 5 divided by 100: 0.05.

The point moves 2 places to the left.

5% = 5 ÷ 100 = 0.05

The tax is 5% of $36.

"Of" means times: 0.05 times $36.

That is $1.80.

tax = 0.05 × $36 = $1.80

To multiply decimals: first 5 times 36, as whole numbers.

That is 180.

Then count the decimal places: 2.

So it is 1.80.

5 × 36 = 180

2 decimal places: 1.80

4 Add it on

The tax is added to the price.

$36 plus $1.80 is $37.80.

total = $36 + $1.80 = $37.80

So the final price is $37.80.

5 Check

Let's check another way: we pay 100% minus 40%: 60% of the price.

0.6 times $60 is $36.

100% − 40% = 60%: 0.6 × $60 = $36

Then: we pay 100% plus 5%: 105% of the price.

1.05 times $36 is $37.80.

The same.

So the answer is right!

100% + 5% = 105%: 1.05 × $36 = $37.80

Let's look back.

First: find the discount.

Then: take it off.

Then: find the tax.

Then: add it on.

Last: check.

Answer