A retailer

Hi didieravoaka,

In these types of questions, you have to be careful about how you set up your initial equations; the concept of 'percentage change' works in a very specific way.

We're told that marking up the price of an item 80% leads to a final price of $45...

X + .8X = $45
1.8X = $45
(9/5)X = $45

X = (45)(5/9)
X = 25

Now that we know the original price of the item, we can determine how many MORE dollars must be added to increase the original price 100%

X = 25
A 100% increase in price = 50

Since we're already at $45, we need $5 more.

Final Answer: E

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

A retailer bought a shirt at wholesale and marked it up 80% to its initial retail price of $45. By how many more dollars does he need to increase the price to achieve a 100% markup?

1
2
3
4
5

We can let x = the increased price and create the following proportion:

1.8/45 = 2/x

1.8x = 90

x = 90/1.8 = 50

Thus, the item needs to be marked up by 5 more dollars.

Answer: E