Hi All,

We're told that the main ingredient in a certain prescription drug capsule cost $500 per kilogram. If each capsule contains 600 milligrams of ingredient, what is the cost of the ingredient in a capsule? (1 kilogram = 10^6 milligrams). This is a 'unit conversion' question and comes down to basic Arithmetic. You can do the math in a number of different ways - and if you're concerned about manipulating "big numbers", then you can do several 'smaller decimal shifts' instead.

Since $500 = 1 kilogram = 1,000,000 milligrams
$500 = 1,000,000 milligrams
$50 = 100,000 milligrams
$5 = 10,000 milligrams
$0.50 = 1,000 milligrams

We're asked what 600 milligrams of the drug would cost. Since 600 is less than 1,000 we know that we'll spend LESS than $0.50 on the drug. There's only one answer that fits...

Final Answer: A

GMAT assassins aren't born, they're made,
Rich

BTGmoderatorLU wrote:Source: GMAT Prep

The main ingredient in a certain prescription drug capsule cost $500 per kilogram. If each capsule contains 600 milligrams of ingredient, what is the cost of the ingredient in a capsule? (1 kilogram = 10^6 milligrams)

A. $0.30
B. $0.83
C. $1.20
D. $3.00
E. $3.33

The OA is A.

We can use a proportion to solve this problem. Letting x be the cost, in dollars, per 600-mg capsule, we have:

$500/1 kg = $x/600 mg

Before we can cross multiply, we need the denominators to have the same units. Since we are given 1 kg = 10^6 mg, we have:

$500/10^6 mg = x/600 mg

500/10^6 = x/600

(10^6)(x) = 500(600)

1,000,000(x) = 300,000

10x = 3

x = 0.3

Thus, the cost is $0.30 per capsule.

Answer: A