At a technology consulting firm with x computers, all of which are des

30 are Laptops, then 70 are Desktops;
80 have >1, then 20 have <1;
0.1 of <1 = 0.1*20 = 2;

x=100…D…L………T
>1……[52]…[28]…80
<1……[18]…[2]……20
Total…70…30……100

D=70, D>1=52, 52/70=26/35~25/35~5/7
5/7>3/5? 25>21? yes. 5/7 aprox. 3/4 (75%)

Ans (A)

Let’s say that x = 100 computers
—> 30 laptops and 70 desktops

80 com. > 1 GB
20 com. < 1 GB

10 % of 20 com. = 2 laptops
—> 18 desktops < 1 GB

—> 70 — 18 = 52 desktops > 1 GB
—> \((\frac{52}{70})* 100= \frac{520}{7} ≈ 74.3 %\)

Approximately, 75% of desktops have more than 1 GB RAM.

The answer is A.

GOOD QUESTION!!!

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use 2x2 matris

-----D---L---total
>1gb--52--28--80
<1gb--18--2---20
total--70---30--100
what percent of the desktops have more than 1GB of RAM
52/70 = ~ 75%
IMO A

At a technology consulting firm with x computers, all of which are desktops or laptops, 30% are laptops; if 80% of the total number of computers have more than 1GB of RAM and 10% of the computers with less than 1GB of RAM are laptops (and no computers have exactly 1GM of RAM), approximately what percent of the desktops have more than 1GB of RAM?

(A) 75%
(B) 60%
(C) 52%
(D) 40%
(E) 45%

Let the total number of Computers, which are either laptop or desktop be 100. We are informed that 30% are laptops, hence 70% are desktop, by extension, 30 are laptops and 70 are desktops.
80 pcs have more than 1GB RAM and 20 pcs have less than 1GB RAM.
10% of pcs with less than 1GB RAM are laptops, meaning than 2 laptops have less than 1GB RAM while 18 desktops have less than 1GB RAM.

Desktops with more than 1GB RAM = 70-18 = 52
% of Desktops with more than 1GB RAM = 52*100/70 = 74.3.
From the answer choices only A=75% is close to 74.3 hence we can say approximately 75% of desktops have more than 1GB RAM.

A is the answer.

OFFICIAL EXPLANATION:

In order to solve this problem, it is extremely helpful to set up a matrix, organizing the information and methodically filling it in.

If 30% of the computers are laptops, 70% of the computers are desktops (note: you could not make this inference unless the problem said that all the computers are "desktops or laptops").

If 80% of the computers have more than 1GB of RAM, 20% of the computers have less than 1GB of RAM. (Note: The problem stated that no computers had exactly 1GM of RAM).

If 10% of the computers with less than 1GB of RAM [known to be 20% of all computers] are laptops, then (.1)(.2) = .02 or 2% of all computers are laptops with less than 1GB of RAM.
Laptop Desktop
< 1GB of RAM 2% 20%
> 1GB of RAM 80%
30% 70% x

Since the percents rows must add up, you can fill in the values:
Laptop Desktop
< 1GB of RAM 10% of 20% = 2% 90% of 20% = 18% 20%
> 1GB of RAM 28% 52% 80%
30% 70% x

The final graph is as follows:
Laptop Desktop
< 1GB of RAM 2% 18% 20%
> 1GB of RAM 28% 52% 80%
30% 70% x

Since the question asks "what percent of the desktops [not total number of computers] have more than 1GB of RAM," the correct answer is (percent of desktops with more than 1GB of RAM) / (percent of desktops) = 52%/70% = about 75%

Note: If the concept of dividing percents is causing you trouble, let x = 100 and fill in accordingly.
Laptop Desktop
< 1GB of RAM 2% or 2 18% or 18 20% or 20
> 1GB of RAM 28% or 28 52% or 52 80% or 80
30% or 30 70% or 70 x = 100

If we let x = 100, we have 30 laptops and 70 desktops. Furthermore, 80 computers have more than 1GB of RAM, and 20 computers have less than 1GB of RAM.

Therefore, 20 x 0.1 = 2 are laptops with less than 1GB of RAM, and 18 are desktop with less than 1 GB of RAM. Since there are 70 desktops, 70 - 18 = 52 desktops have more than 1 GB of RAM. So 52/70 x 100 ≈ 75 percent of the desktops have more than 1 GB Of RAM.

Answer: A

At a technology consulting firm with x computers, all of which are desktops or laptops, 30% are laptops; if 80% of the total number of computers have more than 1GB of RAM and 10% of the computers with less than 1GB of RAM are laptops (and no computers have exactly 1GM of RAM), approximately what percent of the desktops have more than 1GB of RAM?

	Desktops	Laptops	Total
Less than 1 GB of RAM	.2x-.02x=.18x	.1*.2x=.02x	.2x
More than 1 GB of RAM	.7-.18x=.52x		.8x
Total	.7x	.3x	x

The percent of the desktops have more than 1GB of RAM = .52x/.7x = 74.28% = 75% approx

IMO A

Plug in computers as 100. After filling all the info from question, you should arrive at there being 70 desktops, out of which 52 have more than 1GB RAM. So dont make the mistake of doing 52/100, rather do 52/70 (Desktops with more than 1 GB RAM/Desktops). You should arrive at 520/7 = 75% approx.