A computer store sells two sizes of laptops, 13-inch and 15-inch. Duri

Question

A computer store sells two sizes of laptops, 13-inch and 15-inch. During a typical week, the store sells two 13-inch laptops for every 15-inch laptop. However, during the holiday season, the number of 13-inch laptops sold decreases by 50 percent, and the number of 15-inch laptops sold triples. If the store sells 600 laptops per week during the holiday season, how many more 15-inch laptops than 13-inch laptops are sold?

A. 100
B. 150
C. 200
D. 300
E. 400

A. 100
B. 150
C. 200
D. 300
E. 400

BrentGMATPrepNow · Accepted Answer

During a TYPICAL week, the store sells two 13-inch laptops for every 15-inch laptop.  
Let  x  = the number of 15-inch laptops TYPICALLY sold each week
So,  2x  = the number of 13-inch laptops TYPICALLY sold each week

However, during the HOLIDAY season, the number of 13-inch laptops sold decreases by 50 percent, and the number of 15-inch laptops sold triples.  
So, 50% of  2x  = the number of 13-inch laptops sold each week during the HOLIDAYS
In other words,  x  = the number of 13-inch laptops sold each week during the HOLIDAYS

Also, (3)( x ) = = the number of 15-inch laptops sold each week during the HOLIDAYS

If the store sells 600 laptops per week during the holiday season...  
We can write:  x  + (3)( x ) = 600
Simplify: 4x = 600
Solve: x = 150

Since  x  = the number of 13-inch laptops sold each week during the HOLIDAYS, we know that 150 13-inch laptops were sold each week during the HOLIDAYS 
600 - 150 = 450, so 450 15-inch laptops were sold each week during the HOLIDAYS

....how many more 15-inch laptops than 13-inch laptops are sold?  
450 - 150 = 300

Answer: D

Cheers,
Brent

mohshu · Answer

initial ratio is 2:1

then during holiday the rration becomes 1 : 3

so total sale = 600 = 1x + 3x

4x = 600
x =150..

13 inch = 150..
15 inch = 450

450- 150 = 300
ans D

avadavis · Answer

It's D. 300.

300  15-inch laptops  will be sold more than  13-inch laptops  if the store sells 600 laptops per week during the holiday season.

MathRevolution · Answer

Initial ratio of 13 and 15 inches: 2: 1

Holiday ratio: 1 : 3

Total : 600 sold: 150 : 450

Difference: 450 - 150 = 300

Answer D

Kimberly77 · Answer

Hi  BrentGMATPrepNow , when I assign S= 13 inches and L=15 inches > 2S = L
After 50% drop S=3L

S+L = 600
3L+L=600
L=150 , S=450

My confusion is why am I getting opposite result of L & S here?
Thanks Brent

BrentGMATPrepNow · Answer

Given: During a TYPICAL week, the store sells two 13-inch laptops for every 15-inch laptop.  
Your equation, 2S = L, doesn't meet the given conditions. 
For example,  S = 5 and L = 10  is a solution to your equation, but  S = 5 and L = 10  doesn't satisfy the condition that  the store sells two 13-inch laptops for every 15-inch laptop

Kimberly77 · Answer

Thanks Brent  BrentGMATPrepNow , not sure that I quite get it as if  S = 5 and L = 10 , then 2S = L > 2(5) = 10 ?
Or should it be S=2L then 50% sales drop of S will become 1/2?

A computer store sells two sizes of laptops, 13-inch and 15-inch. Duri

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