Answer:
Step-by-step explanation:
The total surface area of the sphere = 2πr²
Total surface area of the cylinder = 2πr²+2πrh
Total surface area of the solid = 4πr²+2πrh
r is the radius of the sphere and the cylinder
h is the height of the cylinder
Total surface area of the solid = 2πr(r+h)
If the total height of the solid is 18 cm, then r+h = 18cm
Given the Total surface area of the solid = 205π cm
205π = 2πr(r+h)
205π = 2πr(18)
205π = 36πr
205 = 36r
Divide both sides by 36
205/36 = 36r/36
r = 5.69cm
Since r+h = 18cm
5.69+h = 18
h = 18-5.69
h = 12.31cm
5 red socks are with the 20 black socks
20(1/4)=5
Answer: 30
B
