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 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? Answer & Explanation Answer:- 2 Explanation :- Let Total Candidates be =X 3. A student multiplied a number by 3/5 instead of 5/3.What is the percentage error in the calculation? Answer & Explanation Answer:- 1 Explanation :- Let the number be x. 4. 270 students appeared for an examination, of which 252 passed. What is the pass percentage? Answer & Explanation Answer:- 1 Explanation :- Pass %age =(252/270)*100 5. John’s salary was decreased by 50% and subsequently increased by 50%. How much percent does he loss? Answer:- 2 Explanation :- By shortcut method
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
1. 28000
2. 30000
3. 32000
4. 33000
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
1. 64%
2. 32%
3. 34%
4. 42%
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%
1. 93.33%
2. 93.23%
3. 92.23%
4. 92%
Pass %age=93.33%
1. 35%
2. 25%
3. 32%
4. 28%
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%