A vendor bought 40 identical phone chargers for $35 each. The vendor

Question

A vendor bought 40 identical phone chargers for $35 each. The vendor sold some of the chargers at one price and the rest at another price. What was the vendor’s gross profit from selling all 40 chargers?

(1) If the vendor had paid $5 less for each charger, the gross profit would have been $1,900.

(2) If each charger had sold for $3 more, the gross profit would have been $1,820.

M47-222

Bunuel · Accepted Answer

GMAT Club Official Solution:

A vendor bought 40 identical phone chargers for $35 each. The vendor sold some of the chargers at one price and the rest at another price. What was the vendor’s gross profit from selling all 40 chargers?

(1) If the vendor had paid $5 less for each charger, the gross profit would have been $1,900.

Paying $5 less for each of 40 chargers would reduce the total cost by:

40 * 5 = 200

So the actual gross profit was:

1,900 - 200 = 1,700

Sufficient.

(2) If each charger had sold for $3 more, the gross profit would have been $1,820.

Selling each of 40 chargers for $3 more would increase the total revenue by:

40 * 3 = 120

So the actual gross profit was:

1,820 - 120 = 1,700

Sufficient.

Answer: D.

MarkGMATMentor · Answer

This prompt sets up a classic misdirection: making you expect one thing, while the statements give you something else.

You’re given enough information to calculate the cost, partial information on the prices, and then asked for the profit. 
 
The natural inclination is to think that you need the missing information on the charger prices for statements to be sufficient. Since the statements don't do that, you might think that they are insufficient.

Be skeptical when something looks too easy. Though you want to avoid too many calculations, you also need to be clear about what's happening. 
 
Let’s use the profit equation (profit = revenue - cost) with a table to stay organized: 
    
 P 
 = 
 R 
 - 
 C 
 
  Prompt 
 p 
 = 
 r 
 - 
 40($35) 
 
  1 
 $1900 
 = 
 r 
 - 
 40($30) 
 
  2 
 $1820 
 = 
 r + 40($3) 
 - 
 40($35)

Prompt:  you know that the cost is 40($35). You can plug this into the profit equation to get: p = r - 40($35)

Statement 1:  The cost per charger is $5 less, so the cost is now $30 per charger. The revenue hasn't changed, and the profit is now $1900. With the equation from the prompt and the new equation (row "1" in the table), you will be able to solve for p.  Sufficient.

Statement 2:  The revenue per charger is now $3 more. You don't know the original prices, but you still know that the change in revenue is 40($3). Profit is now $1820. Like Statement 1, together with the equation from the prompt this is enough to solve for p.  Sufficient.  The answer is D.

Be careful when a DS prompt is set up to look like you need a particular piece of information for sufficiency.  You might need it, or there might be another way to answer the question definitively.

BongBideshini · Answer

Statement 1 
Cost would have been 5*40 =200 less; profit would have been 200 more
Actual profit =1900 -200 =1700

Statement II 
Selling price would have been 3*40 =120 more; profit would have been 120 more
Actual profit =1820 -120 =1700

Ans D

A vendor bought 40 identical phone chargers for $35 each. The vendor

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	P	=	R	-	C
Prompt	p	=	r	-	40($35)
1	$1900	=	r	-	40($30)
2	$1820	=	r + 40($3)	-	40($35)

GMAT Data Sufficiency (DS) Questions

A vendor bought 40 identical phone chargers for $35 each. The vendor

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