Mensuration (Railway Maths) (Part – III)

Total Questions: 50

21. What will be the area (in cm²) of a semicircle whose perimeter is 72 cm? (Take π = 22/7) [Group D 20/09/2022 (Evening)]

Correct Answer: (a) 308
Solution:

22. Three cubes, each of edge 5 cm, are arranged next to each other. The surface area of the resulting cuboid is: [Group D 20/09/2022 (Evening)]

Correct Answer: (a) 350 cm²
Solution:

23. A triangle and a parallelogram have the same base and the same area. If the sides of the triangle are 26 cm, 28 cm, and 30 cm and the parallelogram stands on a base of 28 cm, then the height of the parallelogram is: [Group D 20/09/2022 (Evening)]

Correct Answer: (c) 12 cm
Solution:

24. If the length of each side of a cube is increased to three times its initial length, then its volume will become ______ times its initial volume. [Group D 22/09/2022 (Morning)]

Correct Answer: (a) 27
Solution:

25. A cube each of whose side is 5 cm will have a total surface area of ____ cm²? [Group D 22/09/2022 (Morning)]

Correct Answer: (c) 150
Solution:

Total surface of cube = 6a²
⇒ 6 × 5 × 5 = 150 cm²

26. The ratio of the volumes of two cylinders A and B having the radii of their bases as 2 cm and 3 cm, respectively, and having the same height, is: [Group D 22/09/2022 (Afternoon)]

Correct Answer: (c) 4 : 9
Solution:

27. 2250 m of wire is used to fence a rectangular plot in three rounds. The length of the plot exceeds the breadth by 5 m. What is the length of the plot? [Group D 26/09/2022 (Afternoon)]

Correct Answer: (d) 190 m
Solution:

28. A solid right cylinder having a base of diameter 10 cm and height 2 cm is melted and recast into right cylindrical coins with a base diameter of 1 cm and a 0.2 cm thickness. Find the number of coins that can be made. [Group D 26/09/2022 (Evening) ]

Correct Answer: (a) 1000
Solution:

29. What is the area of a regular hexagon, the length of each of whose sides is 4 cm? [Group D 27/09/2022 (Morning)]

Correct Answer: (a) 24√3 cm²
Solution:

30. Six equal cubes, each of side 7 cm, are placed adjacent to each other. The volume of the new solid formed will be: [Group D 27/09/2022 (Afternoon)]

Correct Answer: (b) 2058 cm³
Solution:

Side of each cube = a = 7 cm
Volume of each cube = a³ = 7³ = 343 cm³
Volume of six equal cubes = 6 × 343
= 2058 cm³