Percentage - Study Mode
[#91] In an examination, 60% of the candidates passed in English and 70% of the candidates passed in Mathematics, but 20% failed in both subjects. If 2500 candidates passed in both the subjects, the number of candidates who appeared at the examination was :
Correct Answer
(D) 5000
Explanation
Solution: Candidates failed in English = (100 - 60)% = 40% Candidate failed in Mathematics = (100 - 70)% = 30% 20% Candidate fail in Both. Candidate only fail in English = 40 - 20 = 20% Candidate only fail in Mathematics = 30 - 20 = 10% Students passed in both subjects = 100 - (20% Candidate fail in Both + Candidate only fail in English + Candidate only fail in Mathematics) = 100 - (20 + 20 + 10) = 50% 50% of students = 2500 Total students = $$frac{{2500}}{{50}} imes 100$$ = 5000
[#92] The value of a property depreciates every year by 10% of its value at the beginning of the year. The present value of the property is Rs. 8100. What was its value 2 years ago ?
Correct Answer
(A) Rs. 10000
Explanation
Solution: 10% = $$frac{1}{10}$$ [x08egin{gathered}
{ ext{Initial }},,,,,,{ ext{Final}} hfill \
,,,{ ext{10}},,,,,,,,,,,,,,,9 hfill \
,,,10,,,,,,,,,,,,,,,9 hfill \
overline {,,100,,,,,,,,,,,,,81,,,} hfill \
end{gathered} ] ⇒ 81 units = Rs. 8100 ⇒ 1 unit = Rs. 100 ⇒ 100 units = Rs. 10000 ⇒ Value of property 2 years ago ⇒ Rs. 10000
[#93] If a man receives on one-fourth of his capital 3% interest, on two third 5% and one the remaining 11%, the percentage interest he receives on the whole is :
Correct Answer
(B) 5%
Explanation
Solution: Let the total capital = 1200 According to the question, one-fourth of 1200 = 300, two third of 1200 = 800, remain 100 Interest on 300 = 3% of 300 = 9 Interest on 800 = 5% of 800 = 40 Interest on 100 = 11% of 100 = 11 Total interest = (9 + 40 + 11) = 60 Required percentage : = $$frac{60}{1200}$$ × 100 = 5%
[#94] The difference between the value of the number increased by 20% and the value of the number decreased by 25% is 36. Find the number ?
Correct Answer
(D) 80
Explanation
Solution: Let the number = x According to the question, ⇒ x × $$frac{120}{100}$$ - x × $$frac{75}{100}$$ = 36 ⇒ 120x - 75x = 3600 ⇒ 45x = 3600 ⇒ x = $$frac{3600}{45}$$ ⇒ x = 80 Hence, required number = 80
[#95] The population of a village has increased annually at the rate of 25%. If at the end of 3 years it is 10000, the population in the beginning of the first year was :
Correct Answer
(A) 5120
Explanation
Solution: 25% = $$frac{1}{4}$$ [x08egin{gathered}
{ ext{Initial }},,,,,,{ ext{Final}} hfill \
,,,4,,,,,,,,,,,,,,,5 hfill \
,,,4,,,,,,,,,,,,,,,5 hfill \
,,,4,,,,,,,,,,,,,,,5 hfill \
overline {,,,,,,64,,,,,,,,,,125,,,} hfill \
end{gathered} ] ⇒ 125 units = 10000 ⇒ 1 unit xa0 xa0 xa0 = 80 ⇒ 64 units = 5120 ⇒ Population at the beginning of 1 st year = 5120