3
Q:

# The average of a set of whole numbers is 27.2. when the 20% of the elements are eliminated from the set of numbers then the average become 34. The number of elements in the new set of numbers can be :

 A) 27 B) 35 C) 52 D) 63

Explanation:

only (c) is correct since it is divisible by 4.

Let the original number of element  be x then the new no.of elements wil be

$\inline&space;\frac{4x}{5}=K$

So K must be divisible by 4

Since,      x =  $\inline&space;\frac{K&space;\times&space;5}{4}$

Q:

In an election between two candidates K and L, the number of valid votes received by K exceeds those received by L by 15% of the total number of votes polled. If 20% of the votes polled were invalid and a total of 8720 votes were polled, then how many valid votes did L get ?

 A) 3241 B) 2457 C) 2642 D) 2834

Explanation:

Let the total number of votes polled in the election be 100k.
Number of valid votes = 100k - 20% (100k) = 80k
Let the number of votes polled in favour of K and L be a and b respectively.
a - b = 15% (100k) => a = b + 15k
=> a + b = b + 15k + b
Now, 2b + 15k = 80k and hence b = 32.5k
It is given that 100k = 8720
32.5k = 32.5k/100k x 8720 = 2834

The number of valid votes polled in favour of L is 2834.

3 135
Q:

In one year, the Amount collected for social welfare, of a village increased by 10% and in the next year, it decreased by 10%. If at the end of 2nd year, the amount was 7920, what was it in the beginning ?

 A) 8800 B) 8650 C) 8000 D) 8980

Explanation:

Let the amount collected be 'A'
Then, from the given conditions,
A x 110/100 x 90/100 = 7920
A x 0.99 = 7920
A = 7920/0.99
=> 8000

3 111
Q:

Express 6.72 % in ratio ?

 A) 65 : 124 B) 42 : 625 C) 21 : 125 D) 37 : 442

Explanation:

6.72/100 = 672/10000 = 42/625

5 135
Q:

A candidate got 35% of the votes polled and he lost to his rival by 2250 votes. How many votes were cast ?

 A) 7500 B) 6200 C) 5600 D) 4700

Explanation:

Let the candidates be A & B
35%-----------A
65%-----------B

Difference of votes (65-35)% = 30%

=>          30% ------- 2250
Then for 100% -------- ?     => 7500

2 192
Q:

Two numbers are 35% and 42% are less than a third number .How much percent is the second number less than the first ?

 A) 10.769 % B) 11.23 % C) 10.4 % D) 9.87 %