Mensuration (Railway Maths) (Part – IX)

Total Questions: 50

21. The perimeter of a square and circumference of a circle are the same. What is the ratio of the area of the square to that of the circle? [RRB NTPC 05/04/2021 (Morning)]

Correct Answer: (a) π : 4
Solution:

22. If a cube of side 20 cm is divided into smaller cubes of side 4 cm, then what is the total number of smaller cubes? [RRB NTPC 05/04/2021 (Morning)]

Correct Answer: (b) 125
Solution:

23. Find the volume of a cuboid, if its length is 2 times more than its breadth and the breadth is 12 cm which is twice its height. [RRB NTPC 05/04/2021 (Evening)]

Correct Answer: (c) 2592 cm³
Solution:

L = 12 + 24 = 36 cm,
b = 12 cm , h = 6 cm
Volume of the cuboid = l × b × h
= 36 × 12 × 6 = 2592 cm³

24. If the length, breadth and height of a room are 30 m, 20 m and 40 m respectively, then what will be the area of the four walls of the room? [RRB NTPC 05/04/2021 (Evening)]

Correct Answer: (b) 4000 m²
Solution:

Given, length = 30 m, breadth
= 20 m and height = 40 m
Area of the four wall = 2 (l + b )h
Area of the four wall = 2 (30 + 20) × 40 = 4000 m²

25. In a right circular cylinder, the ratio of the curved surface area to the total surface area is 2 : 5. Find the ratio of the height to radius of the cylinder. [RRB NTPC 06/04/2021 (Morning)]

Correct Answer: (d) 2 : 3
Solution:

26. The length of a rectangular solar panel is 5% more than its breadth. If the area of the solar panel is 210 m², find its breadth. [RRB NTPC 06/04/2021 (Morning)]

Correct Answer: (c) 10√2 m
Solution:

27. Which one of the following triplets can be the measures of the sides of a triangle? [RRB NTPC 06/04/2021 (Morning)]

Correct Answer: (d) 5, 7, 4
Solution:

Here from the given options only the triplet : 5, 7, 4 can be the measures of the sides of a triangle. Because 5 + 7 > 4 , 7 + 4 > 5 and also 5 + 4 > 7 ;

28. If the radius of a sphere is tripled, then its surface area is increased by: [RRB NTPC 06/04/2021 (Morning)]

Correct Answer: (a) 800%
Solution:

29. A semicircle has been drawn on the length of a rectangle. The area of the shaded region in the figure is: [RRB NTPC 06/04/2021 (Evening) ]

Correct Answer: (b) 63 cm²
Solution:

30. A path, 5m, wide runs around and outside a rectangular plot of land of length 10 m and breadth 8m. The area of path is: [RRB NTPC 07/04/2021 (Morning) ]

Correct Answer: (a) 280 m²
Solution:

Area of path = (10 + 5 + 5) × (8 + 5 + 5) - 10 × 8
= 360 - 80 ⇒ 280 m²