21
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

Answer:   B) 8



Explanation:

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

Volume of the cube = (20x20x20)\inline \fn_jvn cm^3  = 8000\inline \fn_jvn cm^3

Volume of the block= (5x10x20)\inline \fn_jvn cm^3 = 1000\inline \fn_jvn cm^3

Number of blocks = (8000/1000) = 8

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
 
Answer & Explanation Answer: C) 3:4

Explanation:

bank

Report Error

View Answer Workspace Report Error Discuss

4 19
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
 
Answer & Explanation Answer: C) 4312 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 = ∏ - ∏ 

= ∏{1762/∏∏ - 1322/∏∏}

= 1762/∏ - 1322/∏

= (176 - 132)(176 + 132)/∏

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

Report Error

View Answer Workspace Report Error Discuss

2 596
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
 
Answer & Explanation Answer: A) 100 π

Explanation:

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

Report Error

View Answer Workspace Report Error Discuss

2 759
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
 
Answer & Explanation Answer: A) 6000

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

Report Error

View Answer Workspace Report Error Discuss

3 421
Q:

A cuboid of dimension 24cm x 9cm x 8 cm is melted and smaller cubers are of side 3 cm is formed.find how many such cubes can be formed ?

A) 64 B) 56
C) 48 D) 40
 
Answer & Explanation Answer: A) 64

Explanation:

Volume of cuboid = (24 x 9 x 8) cm = 1728 cu.cm
Volume of small cube = (3 x 3 x 3) cm = 27 cu.cm
So,
No. of small cubes formed = 1728/27 = 64.

Report Error

View Answer Workspace Report Error Discuss

2 482