Last month a certain music club offered a discount to

SOLUTION

Last month a certain music club offered a discount to preferred customers. After the first compact disc purchased, preferred customers paid $3.99 for each additional compact disc purchased. If a preferred customer purchased a total of 6 compact discs and paid $15.95 for the first compact disc, then the dollar amount that the customer paid for the 6 compact discs is equivalent to which of the following?

(A) 5(4.00) + 15.90
(B) 5(4.00) + 15.95
(C) 5(4.00) + 16.00
(D) 5(4.00 - 0.01) + 15.90
(E) 5(4.00 - 0.05) + 15.95

The cost of 6 compact discs would be $15.95 for the first compact disc plus $3.99 for each of the other 5 discs, so it's \($15.95+5*$3.99\).

We can see that no answer choice matches this value. So, we should manipulate with that expression to get the answer which is listed.

\($15.95+5*$3.99=15.95+5*(4-0.01)=15.95+5*4-0.05=5*4+15.90\).

Answer: A.

Difficulty level changed to 600.
_________________

The first disc is for $15.95 and the 5 subsequent ones for $3.99 each.

Total = 15.95 + 5(3.99)
= 15.95 + 5(4.00-0.01)
= 15.95 + 5(4.00)-0.05
= 15.90 + 5(4.00)

Answer A is correct.

Difficulty level is 600.

The preferred customer paid 15.95 + 5(3.99) dollars for the 6 CDs. However, we don’t see this expression in the answer choices. We can see that had the 15.90 in choice D been 15.95, then D would be the correct answer. Or had the 0.05 in choice E been 0.01, then E would be the correct answer. However, since they aren’t, neither one is the correct answer.

Now let’s analyze the remaining three answer choices. A, B and C. Notice that each one has 4.00, which is 0.01 more than 3.99 and the difference between 5(4.00) and 5(3.99) is 5(0.01) = 0.05. Thus we see that, since 5(4.00) overvalued the cost by 0.05, we must undervalue 15.95 by 0.05 to 15.90 to have an equivalent cost. Thus, equivalently, the customer paid 5(4.00) + 15.90 dollars.

Answer: A
_________________

Hi,

Difficulty level: 600, answer is straight forward, but a little manipulation is required to reach to the answer.

Regards,

Difficulty level 600+. Minor manipulations required. However, very close answer choices might force to mark wrong answer under pressure.

I solved as given below;

3.99*5=19.95+15.95= 35.90 and then just checked the answers matching the total.

Hi Rainman91,

You're asking about two different things, so we'll start with your first question (although it doesn't quite fit with how this question is written). When you face a prompt in which you can TEST THE ANSWERS, the answer choices are almost always written in order (either from least-to-greatest or greatest-to-least) - so if you can determine that an answer is 'too big' or 'too small', then you can eliminate multiple answers (for also being too big or too small). Here though, the answers are NOT written in order (Answers A, B and C get progressively larger, but then D and E are both smaller than Answer A). The answer that you might choose to start with will depend on how the prompt is written (and in some cases, even in how the answer choices are written).

As far as how to work through this question in an efficient fashion (and not spend upwards of 3 minutes on it): like many GMAT questions, this prompt isn't really about doing lots of math - it's about organizing the information that you're given so that you can avoid doing lots of calculations.

Notice how the first disc is $15.95? That's $0.05 LESS than $16.
Notice how the additional discs are all $3.99? That's $0.01 LESS than $4 for each additional disc.

It's interesting that the question tells us that after the first disc is purchased, EXACTLY 5 additional discs are purchases. The total of those 5 additional discs would be $0.05 less than $20. Thinking in these terms (the $0.05 'pieces' that you have to subtract from the 1st disc and the sum of the next 5 discs), the numbers in this prompt are actually pretty easy to combine and simplify.

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

Contact Rich at: Rich.C@empowergmat.com

Its not A.. its E..

(4-.01) that will be is equal to the 3.99 *5+(15.95)..

i dont think so dificulty level wud be 650.. it wub be 550 or 600..
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OHH m wrong .. its A.. i thought in E its .01 but its .05..

Its A..
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1st : 15.95$
Remaining 5 discs : 5 x 3.99
15.95 + 5 x 3.99
15.95 + 5(4 - 0.01)
15.95 + 5x4 - 0.05
15.90 + 5(4)
A

Hi All,

Like many GMAT questions, this prompt isn't really about doing lots of math - it's about organizing the information that you're given so that you can avoid doing lots of calculations.

Notice how the first disc is $15.95? That's $0.05 LESS than $16.
Notice how the additional discs are all $3.99? That's $0.01 LESS than $4.

It's interesting that the question tells us that after the first disc is purchased, EXACTLY 5 additional discs are purchases. The total of those 5 additional discs would be $0.05 less than $20. Thinking in these terms (the $0.05 'pieces' that you have to subtract from the 1st disc and the sum of the next 5 discs), the numbers in this prompt are actually pretty easy to combine and simplify.

Final Answer:

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

1st cd is $15.95
cd 2 to 6 is $3.99 each. if we add $0.01 to these cds it become $4.00 and we can subtract $0.05 from cd 1.
then we will have:
5 * $4.00 + 15.90

Didn't need to pick up the pen for this one.
Merely looking at the answer choices sufficed.

Option (A) takes away 5 cents from the price of first CD $15.95 and adds it to subsequent buys ($3.99 + 1 cent each for 5 CDs).

15.95+5*3.99

= 15.95+5(4.00-0.01) [This is not in the answer choice]

= 15.95+5*4.00-0.05

=15.90+5*4.00

The answer is 5(4.00)+15.90 (A).

All the answer choices include 5(4) so we need to check on an option which is calculated using 5(4)

The preferred customer paid 15.95 + 5(3.99) dollars for the 6 CDs. The answer is 15.95 + 5(4-0.01) = 15.95+20-0.05 = if we check the options, Option (A) can easily be matched with 15.95+20-0.05

I went for option D as the answer. Why can't D be the answer?

5(4.00 - 0.01)+ 15.95 Here, 4.00 - 0.01 = will give us 3.99 right. This is exactly what I got while solving:
5*3.99 + 15.95 right?

Please help me with this doubt

Hi Divya9986,

While you have properly defined the TOTAL cost of the 6 CDs, your result is NOT what is written in Answer D (that option is $3.99 + $15.90, which is $0.05 from your total) - so that is not the correct answer.

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

The money given to the first compact device =15.95

The Remaining 5 discs rate equals : 5 x 3.99

=>15.95 + 5 x 3.99

=>15.95 + 5(4 - 0.01)

=>15.95 + 5x4 - 0.05

=>15.90 + 5(4)
Therefore IMO A

Price of first compact disc=15.95, Price for additional compact disc=3.99.
Since customer purchased 6 compact disc then total amount he paid =15.95+5(3.99)
But since we can't find this expression in answer choice so we will try to rearrange above expression by backtracking the answer choices.
Lets take answer choice A, In this we can see 15.90 instead of 15.95
So lets rearrange our expression as below-
15.90+0.05+5(3.99)-->15.90+5(0.01)+5(3.99)-->15.90+5(3.99+0.01)-->15.90+5(4.00) which is exactly answer choice A.
So Answer is (A).

I have a question. Some say that you should check from E and go above. Some say check C. Others say B and D. There is no hard rule for this. But assuming we are pressed for time and we stick to checking C first. How do we finish under 3 minutes?