A diet contains 300 grams of a mixture of two foods, food X and food Y. Food X contains 10 percent protein and food Y contains 15 percent protein. If a diet provides exactly 38 grams of protein daily, how many grams of food X are in the mixture? Choose the most appropriate option.
A) 150  B) 145  C) 100  D) 160  E) 140
x(10%) y(15%)   38%   23% 28%   the protein parts in the final mixture for X:Y::23:28   hence   23 X   ----------- = --------------   (23+28) 300   23/51 = x/300   x = 23 * 300   ------------   51   hence x is approximately equal to 139.8   hence the answer is 140
<result>E</result>
A diet contains 300 grams of a mixture of two foods, food X and food Y. Food X contains 10 percent protein and food Y contains 15 percent protein. If a diet provides exactly 38 grams of protein daily, how many grams of food X are in the mixture?