Water consists of hydrogen and oxygen, and the approximate ratio, by mass, of hydrogen to oxygen is 2:16. Approximately how many grams of hydrogen are there in 117 grams of water?
Select: A) 7 B) 9 C) 11 D) 13 E) 15
(2/18)*117= 
<gadget id="calculator">(2/18)*117</gadget>
<output>13</output>
13 grams   The answer is 13.
<result>D</result>
Water consists of hydrogen and oxygen, and the approximate ratio, by mass, of hydrogen to oxygen is 2:16. Approximately how many grams of hydrogen are there in 117 grams of water?