Bunuel wrote:

Each M-type unit will increase the base memory capacity of a certain computer by 3 megabytes. What is the base memory capacity, in megabytes, of the computer?

(1) 2 M-type memory units will increase the computer’s base memory by 300 percent.

(2) The memory capacity of the computer after 2 M-type memory units are added to the base memory capacity is 1.6 times the memory capacity after 1 M-type memory unit is added to the base memory capacity.

Kudos for a correct solution.

Target question: What is the base memory in MB of computer? Given: Each M-type memory unit will increase the base memory capacity of a certain computer by 3 MB. Statement 1: 2 M-type memory units will increase the base memory by 300 %. From the given information, we know that 2 M-type memory units will increase the base memory by a total of 6 MB.

Let

x = the BASE memory (in MB) of the computer.

So, with the 2 M-type memory units, the NEW memory is

x + 6 MB

Represents a

300% increase.

FORMULA: P

ercent increase = 100(

new -

old)/

oldSo, we can write:

300 = 100(

x + 6 -

x)/(

x)

Simplify:

300 = 600/x

So, x = 2

In other words,

the BASE memory of the computer is 2 MB.Since we can answer the

target question with certainty, statement 1 is SUFFICIENT

Statement 2: The memory capacity of computer after 2 M-type units are added to base memory capacity is 1.6 times the memory capacity of computer after 1 M-type memory unit is added to the base memory capacity. Let

x = the BASE memory (in MB) of the computer.

So, when TWO M-type memory units are added, the NEW memory is

x + 6 MB

When ONE M-type memory unit is added, the NEW memory is

x + 3 MB

We're told that

x + 6 is 1.6 TIMES

x + 3So, we can write:

x + 6 = 1.6(

x + 3)

At this point, we should recognize that we COULD solve this equation for x, which means we COULD find the

the BASE memory of the computer.Since we COULD answer the

target question with certainty, statement 2 is SUFFICIENT

Answer = D

Cheers,

Brent

_________________

Brent Hanneson – Founder of gmatprepnow.com