A coat costs $120. It is 35% off. What is the sale price? Step by Step

Step by step

The question

Question: A coat costs $120.

It is 35% off.

What is the sale price?

There are four choices.

First we solve it, the normal way.

Then we pick.

1 Find the discount

Percent means out of 100.

So 35% is 35 divided by 100: 0.35.

The point moves 2 places to the left.

35% = 35 ÷ 100 = 0.35

The discount is 35% of $120.

"Of" means times: 0.35 times $120.

To multiply decimals: first 35 times 120, as whole numbers.

That is 4200.

Then count the decimal places: 2, the digits after the point in 0.35.

So it is 42.00.

35 × 120 = 4200

2 decimal places: 42.00

So the discount is $42.

discount = 0.35 × $120 = $42

Careful!

The discount is the money we save.

We still pay the rest.

Careful: $42 is what we save, not what we pay

2 Take it off

A discount comes off the price.

$120 minus $42 is $78.

sale price = $120 − $42 = $78

So the sale price is $78.

3 Check

Let's check another way: we pay 100% minus 35%: 65% of the price.

0.65 times $120 is $78.

The same.

So the answer is right!

100% − 35% = 65%: 0.65 × $120 = $78

4 Pick the choice

Our answer is sale price: $78.

That is choice B.

B) $78

5 Why not the others

A is $42.

Wrong: that is the 35% taken off, not the price.

That is the Careful mistake from before.

A) $42 ✗ that is the 35% taken off, not the price

C is $85.

Wrong: 120 − 35: took away 35 dollars, not 35%.

C) $85 ✗ 120 − 35: took away 35 dollars, not 35%

D is $162.

Wrong: added 35% instead of taking it off.

D) $162 ✗ added 35% instead of taking it off

Let's look back.

First: find the discount.

Then: take it off.

Then: check.

Then: pick the choice.

Last: why not the others.

Answer