Answer:
0.25
Step-by-step explanation:
1. Add up all of the students.
20+20+25+7+13+5+3+2+5=100
2. Make a ratio of that number and the number of all the students in Music/Drama
MUSIC/DRAMA: 7+13+5=25

3. Simplify
= 0.25
\left(\mathrm{Decimal:\quad }x=-0.75\right)
hope it helps :P
10 x 3 x 2 = the volume
10 x 3 = 30
30 x 2 = 60 cm^3
it is cm^3 because all of the numbers you have are in cm