PERCENTAGE & RATIO PROPORTION SET8

Q.1 The population of a city is 5,00,000 out of which 52% are males and rest are females. The overall literacy rate in the city is 70% and 60% of the males are literate. Find the number of educated females in the city and percentage literacy among females.

A) 194000, 80.83%

B) 50000, 20.83%

C) 2,40,000, 50.02%

D) 1,40,000, 40.02%

Ans. A

Total population = 5, 00,000
Number of males = = 2, 60,000
Literate males = = 1,56,000
Number of females = 5,00,000 – 2,60,000 = 2,40,000
Overall literate population = = 3,50,000
Literate females = Overall literate population – literate males
= 3,50,000 – 1,56,000 = 1,94,000
Literate percentage among females = = 80.83%

Q.2 The ratio of the prices of the keyboard and the monitor is 1 : 4. If the price of the monitor increases by 20% and the ratio decreases by 5%, what is the percentage increase/decrease in the price of the keyboard ?

A) 20% increase

B) 4% decrease

C) 6% increase

D) None of these

Ans. B

According to question,
¼ * x/1.2y = 20/100
x/4.8y = 20/100
or x= 96%
x has gone down by 4%

Q.3 In an examination, the number of those who passed and the number of those who failed were in the ratio 5 : 2. Had 25 more appeared, and 5 less passed, the ratio of passed to failed would have been 3 : 2. Find the number of candidates who appeared, initially.

A) 215

B) 210

C) 200

D) 175

Ans. D

Number of those who passed to number of those failed = 5 : 2
Let number of students who passed = 5x
and number of students who failed = 2x
Total number of students = 5x + 2x = 7x
When 25 more students appeared then total students = 7x + 25
When students increased, 5 less passed
Now number of students passed = 5x – 5
Number of students who failed = (7x + 25) – (5x – 5)
= 7x + 25 – 5x + 5 = 2x + 30
New ratio of passed to failure = 3 : 2
According to question
? 2 (5x – 5) = 3 (2x + 30)
10x – 10 = 6x + 90
? 10x – 6x = 90 + 10
4x = 100, x = 25
Hence number of students who appeared =7x
or 7 × 25 = 175.

Q.4 750 candidates appeared in an examination. 70% of the girls and 65% of the boys passed the examination. If total pass percentage was 67%, find the number of boys that appeared in the examination.

A) 400

B) 430

C) 440

D) 450

Ans. D

Apply the Rule of Alligation :

Girls Boys
70 65
67
2 3

Or 3/5 * 750 = 450 boys

Q.5 If the cost of 30 metres of cloth is Rs. 345.Find the cost of 16 metres of cloth ?
A) 185
B) 184
C) 187
D) 188
Ans. B
30 : 16 I I 345 : X
Or X= 16*345/30
= 184