61
Q:

In three coloured boxes - Red, Green and Blue, 108 balls are placed. There are twice as many balls in the green and red boxes combined as there are in the blue box and twice as many in the blue box as there are in the red box. How many balls are there in the green box ?

A) 18 B) 36
C) 45 D) None of these

Answer:   D) None of these



Explanation:

Let R, G and B represent the number of balls in red, green and blue boxes respectively.

Then, 

R + G + B = 108 ...(i),

G + R = 2B ...(ii)

B = 2R ...(iii)

From (ii) and (iii), we have G + R = 2x 2R = 4R or G = 3R.

Putting G = 3R and B = 2R in (i), we get:

R + 3R + 2R = 108 {\color{Blue} \Rightarrow } 6R = 108 {\color{Blue} \Rightarrow } R = 18.

Therefore Number of balls in green box = G = 3R = (3 x 18) = 54.

Q:

Find the least number by which 175760 be divided to make it a perfect cube.

A) 6 B) 10
C) 9 D) 30
 
Answer & Explanation Answer: B) 10

Explanation:

175760 =2³ x 2 x 5 x 13³
= 2³ x 2 x 5 x 13³

To make perfect cube, it must be divided by 2 x 5 = 10

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2 80
Q:

The sum of three consecutive multiples of 3 is 72. What is the second largest number ?

A) 27 B) 24
C) 21 D) 42
 
Answer & Explanation Answer: B) 24

Explanation:

Let the numbers be 3x, 3x + 3 and 3x + 6.
Then,
3x + (3x + 3) + (3x + 6) = 72
9x = 63
x = 7
Largest number = 3x + 6 = 27.

=> Second largest number = 27 - 3 = 24

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1 109
Q:

When 5% is lost in grinding Maize, a country has to import 20 million bags; but when only 2% is lost, it has to import only 15 million bags. Find the quantity of Maize, which grows in the country ?

A) 188 million B) 166 2/3 million
C) 192 3/4 million D) None
 
Answer & Explanation Answer: B) 166 2/3 million

Explanation:

5% - 2% = 3%
=> 3% ------ 5 million bags
100% ---- ?
=> 166 2/3 million bags.

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2 139
Q:

If x = √8 - √7, y = √6 - √5 and z = √10 - 3, which of the following is true  ?

A) x > y < z B) x < y < z
C) x > y > z D) z < x < y
 
Answer & Explanation Answer: D) z < x < y

Explanation:

x = √8 - √7 = 1/(√8 + √7) and y = √6 - √5 = 1/(√6 + √5) and z = √10 - 3 = 1/(√10 + 3)

As (√8 + √7) > (√6 + √5), (√8 - √7) < (√6 - √5)

As (√10 + 3) > (√8 + √7) > (√6 + √5)

z < x < y.

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1 122
Q:

Difference between two numbers is 5, six times of the smaller lacks by 6 from the four times of the greater. Find the numbers ?

A) 12 & 7 B) 13 & 8
C) 15 & 10 D) 14 & 9
 
Answer & Explanation Answer: A) 12 & 7

Explanation:

x – y = 5

4x – 6y = 6

x = 12 y = 7

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2 147