Percentage - Study Mode
[#546] Nagaraj could save 10% of his income. But 2 years later, when his income increased by 20%, he could save the same amount only as before. By how much percentage has his expenditure increased ?
Correct Answer
(A) $$22frac{2}{9}\% $$
Explanation
Solution: Let, his income be = Rs. 100 Saving = Rs. 10 Expenditure = Rs. 90 Increased income = Rs. 120 Increased expenditure = Rs. 110 Increased in expenditure : $$eqalign{
& = frac{{110 - 90}}{{90}} imes 100 cr
& = frac{{200}}{9} cr
& = 22frac{2}{9}\% cr} $$
[#547] 6 c.c. of a 20% solution of alcohol in water is mixed with 4 c.c. of a 60% solution of alcohol in water. The alcoholic strength of the mixture is?
Correct Answer
(C) 36%
Explanation
Solution: Quantity of alcohol in 10 c.c. solution = (20% of 6 + 60% of 4) c.c. = $$left( {frac{{20}}{{100}} imes 6 + frac{{60}}{{100}} imes 4}
ight)$$ xa0 xa0c.c. = (1.2 + 2.4) c.c. = 3.6 c.c. ∴ Required strength : $$eqalign{
& = left( {frac{{3.6}}{{10}} imes 100}
ight)\% cr
& = 36\% cr} $$
[#548] A housewife saved Rs. 2.50 in buying an item on sale. If she spent Rs. 25 for the item, approximately how much percent she saved in the transaction ?
Correct Answer
(B) 9%
Explanation
Solution: Actual price : $$= Rs. (25 + 2.5)$$ $$= Rs. 27.50$$ ∴ Saving : $$eqalign{
& = left( {frac{{2.50}}{{27.50}} imes 100}
ight)\% cr
& = frac{{100}}{{11}}\% cr
& = 9frac{1}{{11}}\% approx 9\% cr} $$
[#549] If Rs. 2800 is $$frac{2}{7}$$ percent of the value of a house, the worth of the house (in Rs.) is :
Correct Answer
(B) 980000
Explanation
Solution: Let the worth of the house be Rs. x Then, $$frac{2}{7}$$% of x = 28000 $$eqalign{
& Rightarrow left( {frac{2}{7} imes frac{1}{{100}} imes x}
ight) = 2800 cr
& Rightarrow x = left( {frac{{2800 imes 100 imes 7}}{2}}
ight) cr
& Rightarrow x = 980000 cr} $$
[#550] Two persons contested an election of Parliament. The winning candidate secured 57% of the total votes polled and won by a majority of 42000 votes. The number of total votes polled is :
Correct Answer
(C) 300000
Explanation
Solution: Let the total number of votes = 100x Winner candidate get 57% of vote i.e. = 57x and losser will get = 100x - 57x = 43x According to the question, 57x - 43x = 42000 ⇒ 14x = 42000 ⇒ x = 3000 Total votes = 100x = 100 × 3000 = 300000