factory-installed memory

[sanju09]

Purchasers of a certain electronic device are given the option of expanding the factory-installed RAM memory capacity at a cost of $60 per additional megabyte of memory capacity. What is the size, in megabytes, of the factory-installed memory capacity?
(1) The cost of expanding the memory capacity by 50 percent is $240.
(2) A version of the device with expanded memory costing $240 has 3/4 as much memory as a version of the device with an expanded memory costing $480.


IMO D

[DanaJ]

Say x = factory-installed memory capacity.
1. Expanding the capacity by 50% means that you expand by an additional 50% of x or 0.5x with $240. Since you pay $60 per megabyte, then you pay for 240/60 = 4 megabytes. This means that 0.5x = 4, making x = 8.

2. Again, you have 4 megabytes extra memory for the price of $240 and 8 megabytes for $480. Since the first version has 3/4 as much memory as the version with 8 added megabytes, you get this equation:
x + 4 = 3/4(x + 8), so you can easily find x.

This means that your answer is correct.

[sanju09]

Say x = factory-installed memory capacity.
1. Expanding the capacity by 50% means that you by an additional 50% of x or 0.5x with $240. Since you pay $60 per megabyte, then you pay for 240/60 = 4 megabytes. This means that 0.5x = 4, making x = 8.

2. Again, you have 4 megabytes extra memory for the price of $240 and 8 megabytes for $480. Since the first version has 3/4 as much memory as the version with 8 added megabytes, you get this equations:
x + 4 = 3/4(x + 8), so you can easily find x.

This means that your answer is correct.

You make things look so simple, Danaj; it's really gr8! But you occasionally make certain spelling and Grammar errors in your explanations, which are harmful on GMAT.

[DanaJ]

Sorry, I was in a hurry; made some corrections. If you still see any, then please let me know.