Ram, a farmer, managed to grow shaped-watermelons inside glass cases of different shapes. The shapes he used were: a perfect cube, hemi-spherical, cuboid, cylindrical along with the normal spherical shaped watermelons. Thickness of the skin was same for all the shapes. Each of the glass cases was so designed that the total volume and the weight of all the watermelons would be equal irrespective of the shape. A customer wants to buy watermelons for making juice, for which the skin of the watermelon has to be peeled off, and therefore is a waste. Which shape should the customer buy?
Show Hint
- In practical applications (like packaging, fuel tanks, or fruits), spheres give maximum efficiency.
- Cube
- Hemi-sphere
- Cuboid
- Cylinder
- Normal spherical
The Correct Option is
Solution and Explanation
Step 2: For the same volume, the shape with the least surface area will waste the least skin.
Step 3: Among all 3D shapes, the sphere has the minimum surface area for a given volume (isoperimetric property).
Step 4: Hence, the spherical watermelons will have the least proportion of skin to pulp, giving maximum juice.
\[ \boxed{\text{Normal spherical}} \]
Top Questions on Mensuration
- The base diameter of a cylinder is 21 cm and the height is 28 cm, then:
(A) Radius of cylinder = 10.5 cm
(B) Volume = 12936 cm\(^3\)
(C) Curved Surface Area = 1848 cm\(^2\)
(D) Total surface area = 2541 cm\(^2\)
Which of the following is/ are correct?
Choose the correct answer from the options given below: - Four circles of equal radius are drawn with centers, A, B, C and D such that ABCD is a square of side 14 cm and the circles touch externally as in the figure. The area of the shaded region bounded by the 4 circles is: (Take \( \pi = \frac{22}{7} \))
- There are five dustbins along a circular path at different places. Ramesh takes multiple rounds of the path every morning, always at the same speed. He noticed that it took him a different number of steps to walk between any two consecutive dustbins. Ramesh also noticed that starting from any of the dustbins, it took a minimum 360 steps to reach every second dustbin, and a maximum 1260 steps to reach every third dustbin. If Ramesh's step size is 0.77 meter, and the width of the path is negligible, which of the following can be the radius of the circular path?
- A farmer has a quadrilateral parcel of land with a perimeter of 700 feet. Two opposite angles of that parcel of land are right angles, while the remaining two are not. The farmer wants to do organic farming on that parcel of land. The cost of organic farming on that parcel of land is Rs. 400 per square foot.
Consider the following two additional pieces of information:
1. The length of one of the sides of that parcel of land is 110 feet.
2. The distance between the two corner points where the non-perpendicular sides of that parcel of land intersect is 265 feet.
To determine the amount of money the farmer needs to spend to do organic farming on the entire parcel of land, which of the above additional pieces of information are MINIMALLY SUFFICIENT? - Adu and Amu have bought two pieces of land on the Moon from an e-store. Both the pieces of land have the same perimeters, but Adu’s piece of land is in the shape of a square, while Amu’s piece of land is in the shape of a circle. The ratio of the areas of Adu’s piece of land to Amu’s piece of land is:
Questions Asked in XAT exam
Match the following renowned Indian personalities with their respective awards.
Names Award 1. Shri Ratan Naval Tata A. Dadasaheb Phalke Award 2. Manmohan Singh B. Grammy Awards 3. Zakir Hussain C. Carnegie Medal of Philanthropy 4. Shyam Benegal D. World Statesman Award - XAT - 2025
- Famous personalities and their contributions
Match the following authors with their respective works.
Authors Books 1. Andy Weir A. Dune 2. Cixin Liu B. The Time Machine 3. Stephen Hawking C. The Brief History of Time 4. HG Wells D. The Martian 5. Frank Herbert E. The Three Body Problem - XAT - 2025
- Books and Authors
Match the following airlines with the countries where they are headquartered.
Airlines Countries 1. AirAsia A. Singapore 2. AZAL B. South Korea 3. Jeju Air C. Azerbaijan 4. Indigo D. India 5. Tigerair E. Malaysia - XAT - 2025
- Business and Economy
The diagram below represents a road network connecting five towns, namely Meeren, Lannisport, Winterfell, Oldtown, and Gulltown. The maximum speed limits along any stretch of road are as shown in the diagram. The straight road that connects Meeren to Gulltown passes through Oldtown. Another straight road, running west to east, connecting Meeren to Winterfell, passes through Lannisport. Further, two straight roads, one from Lannisport to Oldtown and another from Winterfell to Gulltown, are perpendicular to the road joining Meeren to Winterfell, and run from south to north.
Consider a car always travelling at the maximum permissible speed, and always taking the shortest route. It takes 1 hour to reach Oldtown from Meeren, 2 hours to reach Gulltown from Oldtown, and 45 minutes to reach Winterfell from Gulltown. (For this problem, always consider the shortest route in terms of distance.)
- XAT - 2025
- Logical and Analytical Reasoning Skills
The plots below depict and compare the average monthly incomes (in Rs. ’000) of males and females in ten cities of India in the years 2005 and 2015. The ten cities, marked A-J in the records, are of different population sizes. For a fair comparison, to adjust for inflation, incomes for both the periods are scaled to 2025 prices. Each red dot represents the average monthly income of females in a particular city in a particular year, while each blue dot represents the average monthly income of males in a particular city in a particular year. The gender gap for a city, for a particular year, is defined as the absolute value of the average monthly income of males, minus the average monthly income of females, in that year.
- XAT - 2025
- Data Interpretation