Percentage - Study Mode

[#46] When the price of an article was reduce by 20%, its sale increased by 80%. What was the net effect on the sale ?
Correct Answer

(A) 44% increase

Explanation

Solution: Let conside 100 item sold on Rs.100 ∴ Total Amount = 100 × 100 = Rs. 10000 Now After 20% discount price become Rs.80 Total Number of Sale increased after discount is 80%. i.e. 100 + 80% of 100 = 180(Item sold) ∴ Total Amount = 180 × 80 = Rs. 14400 Increased in amount = 14400 - 10000 = 4400 % Increase in amount = $$frac{{4400 imes 100}}{{10000}} $$ = 44% (increase)

[#47] In an examination, 34% failed in Mathematics and 42% failed in English. If 20% failed in both the subjects, the percentage of students who passed in both subjects was :
Correct Answer

(C) 44%

Explanation

Solution: Failed students in Mathematics = 34% Failed students in English = 42% Student failed in both subject math and english = 20% Student only fail in Math = 34 - 20 = 14% Student only fail in English = 42 - 20 = 22% Percentage of passed students in both subjects : = 100 - [ student fail in maths + student fail in english + student fail in both subject] = [100 - (14 + 20 + 22)] = 44%

[#48] In an election there were only two candidates. One of the candidate secured 40% of votes and is defeated by the other candidate by 298 votes. The total number of votes polled is :
Correct Answer

(C) 1490

Explanation

Solution: Let the total number of the voter is 100x and the winner get 60x votes and loser get 40x votes. ∴ According to question 60x - 40x = 298 ⇒ x = $$frac{298}{20}$$ ∴ Total Number of voter = 100 × $$frac{298}{20}$$ xa0 = 1490

[#49] In what ratio must a mixture of 30% alcohol strength be mixed with that of 50% alcohol strength so as get a mixture of 45% alcohol strength ?
Correct Answer

(B) 1 : 3

Explanation

Solution: By using Alligation rule, Hence, required ratio = 1 : 3

[#50] When 60% of a number is subtracted from another number, the second number reduces to its 52%, the ratio of the first number to the second number is :
Correct Answer

(D) 4 : 5

Explanation

Solution: Let the first and second number is a and b respectively, b - $$frac{60a}{100}$$ = $$frac{52b}{100}$$ b - $$frac{52b}{100}$$ = $$frac{60a}{100}$$ $$frac{48b}{100}$$ = $$frac{60a}{100}$$ 4b = 5a $$frac{a}{b}$$ = $$frac{4}{5}$$ ⇒ a : b = 4 : 5