Answer: a. 20
b. [tex]T=D+5[/tex] Â Â
c. 9
Step-by-step explanation:
Given : The band director insists that there are to be 5 more trumpet players than drummers at all times. (1)
a.The high school marching band has 15 drummers this year.
Then, the number of  trumpet players in the marching band this year will be :-
[tex]15+5=20[/tex]
The marching band has 20 trumpet player this year.
b.  Let  the number of trumpet players  is denoted by T and the number of drummers is denoted by D.
Then, according to statement (1), we have
[tex]T=D+5[/tex] Â Â Â Â Â Â Â Â Â Â Â (2)
Expression that describes the relationship of the number of trumpet players (T) and the number of drummers (D) : [tex]T=D+5[/tex] Â Â
c. If T= 14, then substitute it in (2), we get
[tex]14=D+5[/tex] Â Â Â
Subtract  5 from both sides , we get
[tex]9=D\ \ or\ D=9[/tex]
Hence, the band director want 9 drummers in the band .