Answer:
Let the number of people that wore black pants be
Let the number of people who wore blue pants be
The total number of students in the choirs is
Three times as many students wore black pants as blue jeans can be represented below as
The total number of students will be represented below as
Substitute the equation (1) in equation (2)
Hence,
The number of students who wore blue pants is =11
The right answer is OPTION D