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A doctor prescribed 18 cubic centimeters

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A doctor prescribed 18 cubic centimeters

by rsarashi » Thu Feb 09, 2017 9:25 am
A doctor prescribed 18 cubic centimeters of a certain drug to a patient whose body weight was 120 pounds. If the typical dosage is 2 cubic centimeters per 15 pounds of the body weight, by what percent was the prescribed dosage greater than the typical dosage?

A) 8%

B) 9%

C) 11%

D) 12.5%

E) 14.8%

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by Brent@GMATPrepNow » Thu Feb 09, 2017 9:35 am
A doctor prescribed 18 cubic centimeters of a certain drug to a patient whose body weight was 120 pounds. If the typical dosage is 2 cubic centimeters per 15 pounds of the body weight, by what percent was the
prescribed dosage greater than the typical dosage?

A) 8%
B) 9%
C) 11%
D) 12.5%
E) 14.8%
We can use equivalent ratios to determine what the dosage SHOULD have been.
We'll use the ratio of drug dosage (in cubic centimeters)/body weight (in pounds)

Let x = the dosage (in cubic centimeters) the patient SHOULD have received

We get: 2/15 = x/120
Cross multiply to get: 15x = (2)(120)
Simplify: 15x = 240
Solve: x = 16
So, the patient SHOULD have received a dosage of 16 cubic centimeters
Instead, the patient was prescribed a dosage of 18 cubic centimeters

Percent increase = 100(new - original)/original
= 100(18 - 16)/16
= 200/16
= 12.5

Answer: D

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by [email protected] » Thu Feb 09, 2017 9:42 am
Hi rsarashi,

This question is essentially about working through the necessary arithmetic. Thankfully, the math itself isn't that tough, but you do have to stay organized to make sure that you're setting up the proper calculations.

We're told that a typical dose of a drug is 2 cm^3 per 15 pounds. With a 120 pound person, there are 8 15-pound "sets", so the typical dose would be 8(2 cm^3) = 16 cm^3. Since the doctor prescribed 18 cm^3 of the drug, the dose was clearly larger than the typical dose. The question asks by what percent greater was that dose.

Since 18 is "2 more" than 16, we can know that the prescribed dose was 2/16 = 1/8 = 12.5% greater than it typically would be.

Final Answer: D

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by DavidG@VeritasPrep » Thu Feb 09, 2017 9:45 am
rsarashi wrote:A doctor prescribed 18 cubic centimeters of a certain drug to a patient whose body weight was 120 pounds. If the typical dosage is 2 cubic centimeters per 15 pounds of the body weight, by what percent was the prescribed dosage greater than the typical dosage?

A) 8%

B) 9%

C) 11%

D) 12.5%

E) 14.8%

OAD
We could also do a little back-solving here. The easiest answer choice to test would be D, as 12.5% converts to a nice fraction, 1/8. If 18 is 1/8 more than the appropriate amount, then 18 is 9/8 of this amount. 18 = (9/8)x --> 16 = x. If the appropriate amount is 16, and the weight is 120, we get a ratio of 16/120 or 2/15. That's what we want! The answer is D
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by shashank.ism » Fri Feb 10, 2017 4:41 am
rsarashi wrote: A doctor prescribed 18 cubic centimeters of a certain drug to a patient whose body weight was 120 pounds. If the typical dosage is 2 cubic centimeters per 15 pounds of the body weight, by what percent was the prescribed dosage greater than the typical dosage?

A) 8%

B) 9%

C) 11%

D) 12.5%

E) 14.8%

OAD
Dose is 2 cc per 15 pound.
Patient weight is 120 pound.
The dose required by patient is 120/15 x 2 = 16 cc

Dose recommended by doctor is 18 cc.
Percentage by which prescribed dose is higher = 2/16 x 100 = 12.5% Answer D
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by Jeff@TargetTestPrep » Wed Feb 15, 2017 9:39 am
rsarashi wrote:A doctor prescribed 18 cubic centimeters of a certain drug to a patient whose body weight was 120 pounds. If the typical dosage is 2 cubic centimeters per 15 pounds of the body weight, by what percent was the prescribed dosage greater than the typical dosage?

A) 8%

B) 9%

C) 11%

D) 12.5%

E) 14.8%
The typical dosage is 2 cubic centimeters (cc) per 15 pounds of body weight. We can set up a proportion to determine what the typical number of cc of the drug would be for a patient with a body weight of 120 pounds:

2/15 = x/120

240 = 15x

240/15 = x

16 = x

Thus, the typical dose for this 120-pound patient is 16 cc. To determine the percent greater than this dose that 18 cc would be, we can use the percent change formula.

(Doctor dose - typical dose)/typical dose x 100%

(18 - 16)/16 x 100% = 2/16 x 100% = 0.125 x 100% = 12.5%

Answer: D

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