Question: 21 -

3/20 is what percent of 12/25? 

31.25%

42.75%

40.5%

35.5%

Answer:

31.25%

Solution:

Let the required percentage be x%.
3/20 = x% of 12/25 => 3/20 = x/100 * 12/25
=> 12x = (300 * 25)/20 => x = (25 * 25)/20
=> x = 31.25%.

Question: 22 -

If the price of an article went up by 20%, then by what percent should it be brought down to bring it back to its original price?

20%

67/3%

32/3 %

15%

Answer:

32/3 %

Solution:

Let the price of the article be Rs. 100.
20% of 100 = 20.
New price = 100 + 20 = Rs. 120
Required percentage = (120 - 100)/120 * 100
= 20/120 * 100 = 50/3 = 16 2/3%

Question: 23 -

 When the numerator of a fraction is decreased by 25% and its denominator is decreased by 20%, the new fraction obtained is 3/4. Find the original fraction? 

5/4

6/7

7/6

4/5

Answer:

4/5

Solution:

Let the fraction be x/y.
When the numerator decreased by 25% and the denominator decreased by 20%.
(x * 3/4)/(y * 4/5) = 3/4 => x/y = 3/4 * (4/5)/(3/4) = 4/5

Question: 24 -

If 25% of x is 15 less than 15% of 1500, then x is? 

720

820

840

750

Answer:

840

Solution:

25% of x = x/4 ; 15% of 1500 = 15/100 * 1500 = 225
Given that, x/4 = 225 - 15 => x/4 = 210 => x = 840.

Question: 25 -

If 15% of 30% of 50% of a number is 90, then what is the number? 

3050

4000

4400

4500

Answer:

4000

Solution:

Let the number be a
Given, 15/100 * 30/100 * 50/100 * a = 90
=> 3/20 * 3/10 * 1/2 * a = 90
=> a = 10 * 20 * 10 * 2 = 4000.