A diet contains 400 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 50 grams of protein daily, how many grams of food X are in the mixture?  Choose the correct choice from the following
A) 120 B) 140 C) 150 D) 160 E) 200
Let x be the number of grams of food X in the mixture.   0.1x + 0.15(400-x) = 50   0.05x = 10   x = 200   The answer is 200.
<result>E</result>
A diet contains 400 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 50 grams of protein daily, how many grams of food X are in the mixture?