Which one of the following diets or the combination of diets supplies

Question

https://gmatclub.com/forum/download/file.php?id=47443 Which one of the following diets or the combination of diets supplies more protein for every dollar? (A) Food A (B) Food B (C) Food C (D) 60% food B and 40% food C (E) 60% food A and 40% food C 2019-04-18_0829.png

AkshdeepS · Accepted Answer

Let me bring some common numbers to solve this problem :

We know the "numbers" in "cost column" are all prime, so take LCM of costs - $2, $3, $7 have LCM = $ 42

So, In $42 amount, I can buy,

Food A = 10/2*42 = 210 gms

Food B = 10/3*42 = 140 gms

Food C = 10/7*42 = 60 gms

Now,

A. Food A contains 10% protein = 0.1*210 = 21 gms of protein

B. Food B contains 20% protein = 0.2*140 = 28 gms of protein

C. Food C contains 30% protein = 0.3*60 = 18 gms of protein

D. 60% of food B & 40% of food C contains = 0.6*140*0.2 + 0.4*60*0.3 = 16.8 + 7.2 = 24 gms

E. 60% of food A & 40% of food C contains = 0.6*210*0.1 + 0.4*60*0.3 = 12.6 + 7.2 = 19.8 gms

Hence B

eswarchethu135 · Answer

2019-04-22_09-42-03.jpg From the above table clearly, only for food B, the protein content per dollar is more compared to that of any other foods or combinations. OPTION: B

stne · Answer

Hi  eswarchethu135 ,

Can you please elaborate , where I am going wrong? Lets take Food B:
10 gms of food for $3 so per dollar 3.33 gms. of food 
Now 20% of this is protein hence  \frac{20}{100} *3.33=.67
Well as you have got 2.22 , can you please tell me where I am going wrong , thank you.

JT2916 · Answer

I did the same thing. I don't know why it's not correct.

yazlal25 · Answer

I think this one is very straightforward.

Since weight of protein is given as a % of total weight of the food, the quantity of the food doesn't matter as long as its same for each food. In the question its 10 grams of each food. So we can directly divide column 2 by column 4 to get the protein per dollar.

Food A = 10% per 2 dollars = 5% per dollar
Food B = 20% per 3 dollars = 6.67% per dollar
Food C = 30% per 7 dollars = 4.3% per dollar

Food D - 60% of B and 40% of C - you dont need to calculate this because it will always be lesser that the same quantity of Food B
Food E - 60% of A and 40% of C - again, need not calculate as it will be less than the same quantity of Food A and B.

Thus, answer is Food B.

Which one of the following diets or the combination of diets supplies

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Which one of the following diets or the combination of diets supplies

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