5
Q:

A cuboidal block 6cm x 9cm x 12cm is cut up into an exact number of equal cubes.The least possible number of equal cubes will be

A) 6 B) 9
C) 24 D) 30

Answer:   C) 24



Explanation:

Volume of block=(6x9x12)\inline \fn_jvn cm^3 = 648\inline \fn_jvn cm^3

Side of largest cube = H.C.F of 6,9,12 = 3cm

Volume of the cube=(3x3x3)=27\inline \fn_jvn cm^3

Number of cubes=(648/27)=24

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
 
Answer & Explanation Answer: A) 3

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.

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13 154
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
 
Answer & Explanation Answer: A) 20

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 = 

=> 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

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7 153
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

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4 241
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

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2 869
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

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3 1318