23
Q:

# The size of the wooden block is 5 x 10 x 20 cm .How many such blocks will be required to construct a solid wooden cube of minimum size?

 A) 6 B) 8 C) 12 D) 16

Explanation:

Side of smallest cube = L.C.M of 5,10,20 = 20cm

Volume of the cube = (20 x 20 x 20)cu.cm  = 8000 cu.cm

Volume of the block= (5x10x20)cu.cm = 1000 cu.cm

Number of blocks = (8000/1000) = 8

Q:

What is the Formula for Volume?

The formula to find the volume is given by just multiplying Length, Breadth and Height of that object.

• Thus V = L x B X H

Volume Formulae ::

1. Volume of Cube of side 's' = s x s x s = ${\mathbit{s}}^{\mathbf{3}}$  cubic units.

2. Volume of Cylinder.

101
Q:

If radius and height of a cylinder increase by 20% and15% respectively. then what is the % change in curved surface area?

 A) 41% B) 38% C) 33% D) 44%

Explanation:

% Change in Curved Surface Area is given by

=>

4 70
Q:

A town has a population of 4000 requires 140 liters of water per head. It has a tank measuring 18m x 12m x 8m. The water of this tank will suffice for ____ days?

 A) 3 B) 4 C) 5 D) 2

Explanation:

Water required = 4000 x 140 = 560000 lit = 560 cu.m (1 cu.m = 1000 lit)

Volume of tank = 18 x 12 x 8 = 1728 cu.m

Water of this tank will suffice for = 1728/560 = 3 days.

19 337
Q:

A Conical tent was erected by the army at a base camp with height 3 m and base diameter 10 m. If every person requires 3.92 cu.m air, then how many persons can be seated in that tent approximately?

 A) 20 B) 19 C) 17 D) 22

Explanation:

Given height of the conical tent = 3 m

Diameter = 10 => Radius = D/2 = 10/2 = 5 m

Now, as the tent is in the conical form

Volume of the conical tent = $\mathbit{\pi }{\mathbit{r}}^{\mathbf{2}}\frac{\mathbf{h}}{\mathbf{3}}$

=> 22 x 5 x 5 x 3 / 7 x 3

= 22 x 25/7

= 78.54 cu.m

Given each person requires 3.92 cu.m of air

=> Number of persons can be seated in the tent = 78.54/3.92 = 20.03 =~ 20

11 329
Q:

Ratio between heights of two cylinder in the ratio 3:5. Their volumes are in the ratio 27:80. Find ratio between their radius ?

 A) 1:3 B) 2:1 C) 3:4 D) 4:7

Explanation:

7 388
Q:

The circumferences of two circles are 264 meters and 352 meters. Find the difference between the areas of the larger and the smaller circles  ?

 A) 2413 sq.m B) 1234 sq.m C) 4312 sq.m D) 2143 sq.m

Explanation:

Let the radii of the smaller and the larger circles be 's' m and 'l' m respectively.

2∏s = 264 and 2∏l = 352

s = 264/2∏ and l = 352/2∏

Difference between the areas =$\pi {l}^{2}-\pi {s}^{2}$

= ∏{1762/∏∏ - 1322/∏∏}

= 1762/∏ - 1322/∏

= (176 - 132)(176 + 132)/∏

= (44)(308)/(22/7) = (2)(308)(7) = 4312 sq m

8 1068
Q:

If a solid sphere of radius 10 cms is moulded into 8 spherical solid balls of equal radius, then surface area of each ball (in sq.cm) is ?

 A) 100 π B) 101/π C) 99 π/12 D) 54/13π

Explanation:

4/3 π x 10 x 10 x 10 = 8 x 4/3 π rxrxr
r = 5
4π x 5 x 5 = 100π

6 1922
Q:

Calculate the number of bricks, each measuring 25 cm x 15 cm x 8 cm required to construct a wall of dimensions 10 m x 4 m x 5 m when 10% of its volume is occupied by concrete ?

 A) 6000 B) 5400 C) 3800 D) 4700

Explanation:

Let 'B' be the nuber of bricks.

=> 10 x 4/100 x 5 x 90/100 = 25/100 x 15/100 x 8/100 x B

=> 10 x 20 x 90 = 15 x 2 x B

=> B = 6000