Percentage :

1. What percentage is equivalent to 2/5 ?

Solution : 2/5 × 100 = 40%

2. 25 % of 500 = ?

Solution : 25% of 500 = 25/100 × 500 = 125

3. Find a number whose 8% is 144

Solution : Let the required number be X

Then, 8% of X = 144

8/100 X = 144 => X = 100/8 × 144 = 1800

4. If Tommy’s salaries is 20% more than that of Tom, then how much % is Tom’s salary less than that of Tommy’s ?

Solution : Here, X = 20

∴ Required answer = ( X/100 + X × 100 ) %

= ( 20/100 +20 × 100 ) %

= 16.66 %

5. If Y’s income is 20% less than Z’s income, then how much % is Z’s income more than Y’s income ?

Solution : Here, X = 20%

∴ Required answer = ( X/100 – 20 × 100 ) %

= ( 20/100 – 20 × 100 ) %

= 25 %

6. If P is 10% of S and Q is 25% of S then what percentage is P of Q ?

Solution : Here, X = 10 and Y = 25

P = X/Y × 100 % of Q

= 10/25 × 100 % of Q

= 40% of Q

7. Two numbers are respectively 10% and 25% more than a third number. What percent is the first of the second ?

Solution : Here, X= 10 and Y = 25

∴ first number = (100 + X/100 + Y ) × 100% of the second

= (100 + 10/100 + 25 ) × 100% of the second

= 88% of the second

8. If the salary of a person first increased by 30% and thereafter decreased by 24%, what is the net change in his salary ?

Solution : Here X = 30 and Y= 24

∴ The net % change in the salary

= ( X + Y + XY/100 ) %

= ( 30 – 24 – 30 × 24/100 ) %

= 1.2 %

9. In an examination, a student must get 60 % marks to pass. If a student who gets 240 marks, fails by 60 marks, find the maximum marks ?

Solution : Here X = 60, Y= 240 and Z = 60

∴ Maximum marks = 100 (Y+ Z )/X

= 100 (240 + 60 )/60

= 100 × 300/60 = 500

10. In an examination, 32 % students failed in Mathematics and 42 % failed in Science. If 7 % failed both the subjects, find the % those who passed In both the subjects.

Solution : Here X= 32, Y = 42 and Z = 7

∴ Percentage of students passing both the subjects

= (100 – (X + Y – Z ) ) %

= ( 100 – ( 32 + 42 – 7 ) ) %

= 33%