Percentage 7

1. In a certain school, 20% of students are below 8 years of age. The number of students above 8 years of age is 2/3 of the number of students of 8 years of age which is 48. What is the total number of students in the school?
1. 100
2. 102
3. 110
4. 90

Answer & Explanation

Answer:- 1

Explanation :-

Suppose Total Students=X
Students below 8 years age=20% of X
Therefore Students above 8 years and 8 year age=80% of X
80% of x = 48 +2/3 of 48
80% of x=48+32
80% of x=80
Therefore x=100

 

2. In an examination, 5% of the applicants were found ineligible and 85% of the eligible candidates belonged to the general category. If 4275 eligible candidates belonged to other categories, then how many candidates applied for the examination?
1. 28000
2. 30000
3. 32000
4. 33000

Answer & Explanation

Answer:- 2

Explanation :-

Let Total Candidates be =X
Ineligible candidates=5% X
eligible candidates=95% X
4275=95% of X
eligible candidates (General Category)=85% of Eligible candidates
eligible candidates (Other Category)=15% of Eligible candidates
Therefore 4275=15% of 95% of X
X=(4275*100*100)/(15*95)X=3000

 

3. A student multiplied a number by 3/5 instead of 5/3.What is the percentage error in the calculation?
1. 64%
2. 32%
3. 34%
4. 42%

Answer & Explanation

Answer:- 1

Explanation :-

Let the number be x.
By Mistake Multiplied By 3/5 i.e=(3/5)x
But , Correct Result =(5/3)x
Error =((5/3)-(3/5))x
Error=(16/15)x
Error %= Error / Correct Answer
Error %=((16/15)x)/((5/3) x)
Error %=64%

 

4. 270 students appeared for an examination, of which 252 passed. What is the pass percentage?
1. 93.33%
2. 93.23%
3. 92.23%
4. 92%

Answer & Explanation

Answer:- 1

Explanation :-

Pass %age  =(252/270)*100
Pass %age=93.33%

 

5. John’s salary was decreased by 50% and subsequently increased by 50%. How much percent does he loss?
1. 35%
2. 25%
3. 32%
4. 28%

Answer & Explanation

Answer:- 2

Explanation :-

By shortcut method
let X be Increase in %age
let Y be decrease in %age
=>(X + Y +XY/100)
=>(50-50-)+((50*(-50))/100)
=> -25
Therefore  loss of 25%

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