A rabbit on a controlled diet is fed daily 300 grams of a mixture of two foods, food X and food Y. Food X contains 10% protein and food Y contains 15% protein. If the rabbit's diet provides exactly 38 grams of protein daily, how many grams of food X are in the mixture. Choose one:
A) 100
B) 140
C) 150
D) 160
E) 200
0.1x + 0.15y = 38   x+y = 300   x = 300-y   so 0.1(300-y) + 0.15y = 38   30-0.1y + 0.15y = 38   0.05y = 8   y = 160 grams   then x = 140 grams.   Answer: 140
<result>B</result>
A rabbit on a controlled diet is fed daily 300 grams of a mixture of two foods, food X and food Y. Food X contains 10% protein and food Y contains 15% protein. If the rabbit's diet provides exactly 38 grams of protein daily, how many grams of food X are in the mixture.