Given:
Cylinder: height = 16 cm ; radius = 5 cm
cone: height = 12 cm ; radius = 4 cm
Volume of cylinder = 3.14 * (5cm)² * 16cm = 1,256 cm³
Volume of cone = 3.14 * (4cm)² * 12cm/3 = 200.96 cm³
Volume of air space = 1256 cm³ - 200.96 cm³ = 1,055.04 cm³
10 people who build at the same rate can frame a house in 6 days. That means it will take one person
days to finish the house.
Which means that it will take 4 people
days to finish the house.
So, the fractional part of the house 4 people can frame in 3 days will be 
Thus, Option D is the correct answer.
Volume of a quadrangular pyramid=(1/3)bh
b=base
h=height
b=area of the base=area of a square=8.4 ft * 8.4 ft=70.56 ft²
Pythagoras theorem:
hypotenuse²=leg₁² + leg₂²
data:
hypotenuse=9.6 ft
leg₁=height=h
leg₂=8.4 ft /2=4.2 ft
(9.6 ft)²= h² + (4.2 ft)²
92.16 ft²=h²+17.64 ft²
h²=92.16 ft²-17.64 ft²
h²=74.52 ft²
h=√(74.52 ft²)=8.63 ft.
Volume of this quadrangular pyramid=(1/3)(70.56 ft²)(8.63 ft)=202.9 ft³≈202.3 ft³
Answer: ≈202.3 ft³