If right circular cylinders A and B have the same radius : height rati...
Steps 1 & 2: Understand Question and Draw Inferences
Let the radius and height of Cylinder A be RA and HA respectively, and
The radius and height of Cylinder B be RB and HB respectively.
Given:
RA: HA = RB: HB
This equation can also be written as:
RA: RB = HA : HB . . . (1)
We know that the curved surface area of a right circular cylinder, CSA = 2πRH, where R and H are the radius and height of the cylinder respectively.
So, CSAA : CSAB = 2πRA HA : 2πRB HB
CSAA : CSAB = RA HA : RB HB . . . (2)
Substituting (1) in (2), we get:
CSAA : CSAB = RA 2: RB2 = HA 2: HB2 . . . (3)
From Equation (3) it is clear that we will be able to determine the ratio of CSAA : CSAB if we know the ratio RA : RB or the ratio HA : HB
Step 3: Analyze Statement 1
(1) The ratio of the radius of cylinder A to the radius of cylinder B is 2:1
Since the ratio RA : RB is given, we will be able to determine the ratio CSAA : CSAB
Statement 1 is sufficient.
Step 4: Analyze Statement 2
(2) The ratio of the volume of cylinder A to the volume of cylinder B is 8:1
We know that volume of a right circular cylinder, V = πR2 H, where R and H are the radius and height of the cylinder respectively.
So,
VA : VB = πRA 2HA : πRB 2HB
VA : VB = RA 2HA : RB 2HB . . . (4)
Substituting (1) in (4), we get:
VA : VB = RA 3: RB3 . . . (5)
We are given that VA : VB = 8:1
So, from Equation (5), we get:
RA 3: RB3 = 8:1
This means that,
RA : RB = 2:1
Since we have been able to determine the ratio RA : RB is given, we will be able to determine the ratio CSAA : CSAB
Statement 2 is sufficient.
Step 5: Analyze Both Statements Together (if needed)
You get a unique answers in steps 3 and 4, so this step is not required
Answer: Option (D)