Need Help with this !! Experts

[ashish]

Each M type memory unit will increase the base memory capacityof a certain computer by 3 MB. what is the base memory in MB of computer?

I 2 M type memory units will increase the base memory by 300 %.
II The memory capacity of computer after 2 Mtype units are added to base memory capacity is 1.6 times the memory capacity of computer after the M type memory unit is added to the base memory capacity.

[MartyMurray]

Each M type memory unit will increase the base memory capacityof a certain computer by 3 MB. what is the base memory in MB of computer?

I 2 M type memory units will increase the base memory by 300 %.
II The memory capacity of computer after 2 Mtype units are added to base memory capacity is 1.6 times the memory capacity of computer after the M type memory unit is added to the base memory capacity.

Ok, know that each unit increases memory by 3. So it looks as if the question is can we somehow use this to get to the base memory.

Statement 1 says that adding two units increases memory by 300% over base memory, b. We know that two units add up to 6 MB. So if 6 is 300% of b, then we can figure out b. We don't need to calculate b, just to know that we can.

Sufficient

Statement 2 says that b + 2 units = 1.6(b + 1 unit). We know the units each add 3 MB, so we can use that in the equation to get b + 6 = 1.6(b + 3) So b + 6 = 1.6b + 4.8 and 1.2 = .6b This can obviously be solved for b. No need to go further.

Sufficient

Choose D.

[Brent@GMATPrepNow]

For statement 2, I believe you need to change "the" to "ONE".

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

1) 2 M-type memory units will increase the base memory by 300 %.
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 ONE M-type memory unit is added to the base memory capacity.

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: Percent increase = 100(new - old)/old
So, 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 ONE 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 + 3
So, 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

[utkalnayak]

Each M type memory unit will increase the base memory capacityof a certain computer by 3 MB. what is the base memory in MB of computer?

I 2 M type memory units will increase the base memory by 300 %.
II The memory capacity of computer after 2 Mtype units are added to base memory capacity is 1.6 times the memory capacity of computer after the M type memory unit is added to the base memory capacity.

D

[Matt@VeritasPrep]

Let's say the base capacity is b.

S1 gives us the equation b + 2*3 = b + (300% of b), which is really b + 6 = 4b, or b = 2. SUFFICIENT

S2 gives us the equation b + 2*3 = 1.6 * (b + 3), which is really b + 6 = 1.6b + 4.8, or b = 2. SUFFICIENT