Mensuration (Railway Maths) (Part – VI)

Total Questions: 50

21. 500 persons are taking a dip in a cuboidal pond, which is 80 m long and 50 m broad. What is the rise in the water level in the pond, if the average displacement of the water by one person is 0.04 m³? [RRB NTPC 13/01/2021 (Evening)]

Correct Answer: (a) 0.5 cm
Solution:

22. If two cubes, each with a side of 10 cm, are joined end to end, then find the surface area of the resulting cuboid. [RRB NTPC 13/01/2021 (Evening)]

Correct Answer: (a) 1000 cm²
Solution:

23. If three cubes whose edges measure 3 cm, 4 cm and 5 cm respectively, are melted to form a single cube, then find the edge of the new cube. [RRB NTPC 16/01/2021 (Morning)]

Correct Answer: (c) 6 cm
Solution:

24. A glass cylinder with diameter 20 cm has water to a height of 9 cm. A metal cube of 8 cm edge is immersed in it completely. Calculate the height water will rise in the cylinder (correct to 1 decimal place) by taking π = 3.142. [RRB NTPC 16/01/2021 (Morning)]

Correct Answer: (b) 1.6 cm
Solution:

25. The area of a square field is 7200 m². How long will a cycle take to cross the field diagonally at a constant rate of 4 km/h? [RRB NTPC 16/01/2021 (Evening)]

Correct Answer: (a) 9/5 minutes
Solution:

26. Find the total surface area of a cone, if its radius and slant height are 2r and (1/2) respectively. [RRB NTPC 17/01/2021 (Morning)]

Correct Answer: (c) πr (4r + 1)
Solution:

27. The area of the greatest circle that can be inscribed inside a square of side 21 cm is: [RRB NTPC 17/01/2021 (Evening)]

Correct Answer: (c) 346.5 cm²
Solution:

28. The floor of a hall is rectangular. Its length is 30 m and breadth is 24 m. How many carpets of size 6 m × 4 m are required to cover it? [RRB NTPC 17/01/2021 (Evening)]

Correct Answer: (d) 30 carpets
Solution:

29. If the length of a rectangular solar panel having an area of 110 m² is 10% more than its breadth, then what will be the breadth? [RRB NTPC 18/01/2021 (Morning)]

Correct Answer: (a) 10 m
Solution:

30. If the outer and inner radii of a circular path are 2a and b, then its area is_________sq units: [RRB NTPC 18/01/2021 (Morning)]

Correct Answer: (c) π (4a² − b²)
Solution: