RRB Nsg. Superintendent-2026 (Shift -2nd)
Non Nursing Subjects
Hard

The volume of a solid cylinder is 80,850 cm3 and its height is 21cm. Find the total surface area of the cylinder.
(Use pi=. 22/7

Appeared in: RRB Nsg. Superintendent-2026 (Shift -2nd)

Explanation

  • The solution involves a two-step process: first finding the radius from the given volume and height, then using the radius to calculate the total surface area.
  • Using the volume formula V = πr²h, the radius (r) is calculated. Given V = 80,850 cm³ and h = 21 cm, we get 80,850 = (22/7) × r² × 21, which simplifies to r² = 1225, so r = 35 cm.
  • Next, the total surface area (TSA) is found using the formula TSA = 2πr(r + h).
  • Substituting the values r = 35 cm and h = 21 cm, we get TSA = 2 × (22/7) × 35 × (35 + 21) = 2 × 22 × 5 × 56 = 12,320 cm².

Why Other Options Were Wrong

  • Option A: This value is incorrect. It may arise from a miscalculation, such as an error in finding the radius or during the final multiplication for the total surface area.
  • Option B: This value is incorrect. It represents a calculation error, possibly in summing the radius and height or in the final multiplication step.
  • Option D: This value is incorrect. It is close to the correct answer but likely results from a minor arithmetic mistake during the calculation process.

Related Visual

Visual explanation — Related Visual
  • Visual 1: Diagram - An annotated diagram of a solid cylinder, clearly labeling the radius (r), height (h), the circular top and bottom surfaces (area = πr² each), and the curved side surface (area = 2πrh).
Clinical Relevance
  • Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Calculating the total surface area of a solid cylinder using its volume and height as background academic context rather than a clinical decision trigger.
  • This question assesses fundamental mathematical and problem-solving skills, which are essential for various calculations in healthcare, such as dosage calculations, fluid balance monitoring, and interpreting quantitative data.
  • While not a direct clinical scenario, the logical reasoning and precision required to solve this problem are transferable to the meticulous nature of nursing practice.
  • What if the question asked for the curved surface area instead? The formula would be 2πrh, which would be 2 × (22/7) × 35 × 21 = 4620 cm². This highlights the importance of carefully reading the question to apply the correct formula.
How to Approach the Question
  • First, identify the given information: the volume of the cylinder (80,850 cm³) and its height (21 cm). Also, note the value of π to be used (22/7).
  • Recognize what needs to be calculated: the total surface area (TSA) of the cylinder.
  • Recall the formula for the volume of a cylinder: V = πr²h. Realize that you can use this formula to find the radius (r), which is the missing piece of information needed for the TSA calculation.
  • Substitute the given values into the volume formula and solve for 'r'.
  • Once the radius is found, recall the formula for the total surface area of a solid cylinder: TSA = 2πr(r + h).
  • Substitute the now-known values of r, h, and π into the TSA formula and perform the calculation carefully.
Concept Tested & Keywords
  • Concept Tested: Calculating the total surface area of a solid cylinder using its volume and height.
  • Stem keywords: volume of a solid cylinder, height, total surface area
  • Lead-in keywords: What is

Question ID

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