AAPL wrote:Veritas Prep

Portia purchased a laptop for $480, but after checking the merchant's website realized that she had been overcharged by 20%. By how much, in dollars, was she overcharged?

A. $24
B. $48
C. $80
D. $96
E. $100

OA C.

Let x = the INTENDED price of the laptop

Portia was overcharged by 20%
So, x + (20% of x) = the amount Portia paid
In other words: x + 0.2x = $480
Simplify: 1.2x = 480
Solve: x = 480/1.2 = 400

So, Portia was SUPPOSED to pay $400, but she actually paid $480

So, Portia was overcharged $80

Answer: C

Cheers,
Brent

Hi All,

We're told that Portia purchased a laptop for $480, but after checking the merchant's website realized that she had been overcharged by 20%. We're asked how many dollars she was overcharged. This question can be solved in a couple of different ways, including by TESTing THE ANSWERS.

To start, since $480 is a 'round number', it's likely that the lower number is ALSO a round number (since if we started with a number that was NOT a round number, then increasing that number by 20% would likely lead to an even more-complex number - likely one with cents involved). Working from least to greatest, the first number that would give us another round number would be Answer C - so let's TEST that one first...

Answer C: $80
IF... the overcharge was $80, then....
The lower price is $480 - $80 = $400
20% of $400 = (.2)($400) = $80
This is an exact match for what we were told, so this must be the answer.

Final Answer: C

GMAT assassins aren't born, they're made,
Rich

AAPL wrote:Veritas Prep

Portia purchased a laptop for $480, but after checking the merchant's website realized that she had been overcharged by 20%. By how much, in dollars, was she overcharged?

A. $24
B. $48
C. $80
D. $96
E. $100

OA C.

We can let the actual price = n and create the equation:

1.2n = 480

n = 400

So she was overcharged by 80 dollars.

Answer: C