A luxury liner, Queen Marry II, is transporting several cats as well as the crew (sailors, a cook, and captain) to a nearby port. Altogether, these passengers have 15 heads and 42 legs. How many cats does the ship host?
Choose the most appropriate option
A) 5  B) 6  C) 7  D) 8  E) 9
sa's +co +ca +cats = 15. sa's + 1 +1 +cats =15 or sa's +cats =13.   sa's(2) +2 +2 +cats*4 =42 sa's*2 +cats*4 = 38 or sa's +cats*2 =19 or 13-cats +cat*2 =19   then cats =6   6
<result>B</result>
A luxury liner, Queen Marry II, is transporting several cats as well as the crew (sailors, a cook, and captain) to a nearby port. Altogether, these passengers have 15 heads and 42 legs. How many cats does the ship host?