swerve wrote:In a certain state, gasoline stations compute the price per gallon "p", in dollars, charged at the pump by adding a 4 percent sales tax to the dealer's price per gallon "d", in dollars, and then adding a gasoline tax of $0.18 per gallon. Which of the following gives the dealer's price per gallon "d" in terms of the price per gallon "p" charged at the pump?

A. d = p-0.22
B. d = p/1.22
C. d = p/1.04 - 0.18
D. d= (p-0.18)/1.04
E. d = (p-0.04)/1.18

In a certain state, gasoline stations compute the price per gallon "p", in dollars, charged at the pump by adding a 4 percent sales tax to the dealer's price per gallon "d", in dollars . . .
We can write: p = d + 4% of d
= d + 0.04d
= 1.04d
So, we have: p = 1.04d

. . . and then adding a gasoline tax of $0.18 per gallon.
We get: p = 1.04d + 0.18

Which of the following gives the dealer's price per gallon "d" in terms of the price per gallon "p" charged at the pump?
We need to take p = 1.04d + 0.18 and solve for d

Take: p = 1.04d + 0.18
Subtract 0.18 from both sides to get: p - 0.18 = 1.04d
Divide both sides by 1.04 to get: (p - 0.18)/1.04 = d

Answer: D

Cheers,
Brent

Hi All,

This question can be solved by TESTing VALUES.

P = Price per gallon CHARGED
D = Price per gallon for the Dealer

We're told that the Dealer price has a 4% tax AND 18 cents per gallon added on.

So, I'm going to pick a nice round number for D.

D = $10
P = $10 +4%($10) + 18 cents = 10.40 + .18 = 10.58

Now, we plug in D = 10 and P = 10.58 into the answer choices; there's only one answer that matches...

Final Answer: D

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

swerve wrote:In a certain state, gasoline stations compute the price per gallon "p", in dollars, charged at the pump by adding a 4 percent sales tax to the dealer's price per gallon "d", in dollars, and then adding a gasoline tax of $0.18 per gallon. Which of the following gives the dealer's price per gallon "d" in terms of the price per gallon "p" charged at the pump?

A. d = p-0.22
B. d = p/1.22
C. d = p/1.04 - 0.18
D. d= (p-0.18)/1.04
E. d = (p-0.04)/1.18

The OA is D

Source: GMAT Prep

We see that p = 1.04d + 0.18, so we have:

1.04d = p - 0.18

d = (p - 0.18)/1.04

Answer: D