All of the students of the Music High School are in the band, the orchestra, or both. 80 percent of the students are in only one group. There are 105 students in the band. If 50 percent of the students are in the band only, how many students are in the orchestra only?
Choose the correct choice from the following
A) 42 B) 45 C) 48 D) 51 E) 54
50% of students are in the band only, so 30% of students are in the orchestra only.   Since 20% of students are in both, then 70% of students are in the band which is 105 students.   The number of students in the orchestra is (30%/70%)*105 = 45.   The answer is 45. (30 /70 )*105= 
<gadget id="calculator"> (30 /70 )*105</gadget>
<output>45</output>
45.   The answer is 45.
<result>B</result>
All of the students of the Music High School are in the band, the orchestra, or both. 80 percent of the students are in only one group. There are 105 students in the band. If 50 percent of the students are in the band only, how many students are in the orchestra only?