An astronomer noted that a grouping of red giant stars had an average solar mass of 8 M each, and a grouping of white dwarf stars had an average solar mass of 1.5 M each. If the astronomer calculated the total solar mass of both groupings to be 49 M, what total number of red giant stars and white dwarf stars did the astronomer note?	Choose the correct choice from the following answers:
A) 10  B) 11  C) 12  D) 13  E) 14

Rationale: we can determine quickly that total number should range between 49 / 8 < = n < = 49 / 1.5 , so ans should be between 6 and 33 . now solving the expression 8 a + 1.5 b = 49 decreasing 49 in multiple of 8 and checking divisibility of that number by 1.5 . this way we get 2 red giants , 22 white dwarfs we get 49 , but 2 + 22 = 24 and 24 is not an option . next we get 5 red giants and 6 white dwarfs to get 49 , 5 * 8 + 6 * 1.5 = 49 hence total number is 5 + 6 = 11 ans b
Answer: B