Consider such events:
A - selected student is freshmen
B - selected student is girl
- selected student is freshman is girl
- choosen girl is freshmen.
Use formula
.
From the table you can see that girls that are freshmen are 4 from all 30 people, then
. There are 18 girls, then
. Substitute into the formula:
.
Answer:
.
V = 1/3 l h w
V = 1/3 (12)(15)(9)
V= = 540
answer 540 m^3
Equation (1)

Equation (2)

Get y alone in equation (1)

Insert y in equation (2)
