571. There are three numbers. 5/7th of the first number is equal to 48% of the second number. The second number is 1/9th of the third number. If the third number is 1125, then find 25% of the first number?
A. 168
B. 84
C. 42
D. 21
E. None of these

Explanation:
Let the first number and the second number be F and S respectively.
5/2 F = 48/100 S —-> (1)
S = 1/9 * 1125 = 125
(1) => 5/7 F = 48/100 * 125
=> F = 84
25% of F = 1/4 * 84 = 21.

572. There are two numbers. If 40% of the first number is added to the second number, then the second number increases to its five-fourth. Find the ratio of the first number to the second number?
A. 8 : 25
B. 25 : 8
C. 8 : 5
D. 5 : 8
E. None of these

Explanation:
Let the two numbers be x and y.
40/100 * x + y = 5/4y
=> 2/5 x = 1/4 y => x/y = 5/8

573. Anees spends 40% of his income on rent, 30% of the remaining on medicines and 20% of the remaining on education. If he saves Rs. 840 every month, then find his monthly salary?
A. Rs. 1800
B. Rs. 2000
C. Rs. 2200
D. Rs. 2500
E. None of these

Explanation:
Let’s Aneess salary be Rs. 100.
Money spent on Rent = 40% of 100 = Rs. 40.
Money spent on medical grounds = 30% of (100 – 40) = 3/10 * 60 = Rs. 18.
Money spent on education = 20% of (60 – 18) = 1/5 * 42 = Rs. 8.40
Anees saves 100 – (40 + 18 + 8.40) i.e., Rs. 33.60
for 33.6 —> 100 ; 840 —> ?
Required salary = 840/33.6 * 100 = Rs. 2500

574. In a group of 80 children and 10 youngsters, each child got sweets that are 15% of the total number of children and each youngster got sweets that are 25% of the total number of children. How many sweets were there?
A. 1160
B. 1100
C. 1080
D. 1210
E. None of these

Explanation:
Number of sweets each child got = 15% of 80 = 15/100 * 80 = 12.
Number of sweets 80 children got = 80 * 12 = 960.
Number of sweets each youngster got = 25% of 80 = 25/100 * 80 = 20.
Number of sweets 10 youngsters got = 10 * 20 = 200.
Total number of sweets = 960 + 200 = 1160

575. There is a 30% increase in the price of an article in the first year, a 20% decrease in the second year and a 10% increase in the next year. If the final price of the article is Rs. 2288, then what was the price of the article initially?
A. Rs. 1500
B. Rs. 1800
C. Rs. 2000
D. Rs. 2400
E. None of these

Explanation:
Let the price of the article, four years age be Rs. 100 in the 1st year, price of the article = 100 + 30 = Rs. 130. In the 2nd year, price = 130 – 20% of 130 = 130 – 26 = Rs. 104.
In the 3rd year, price = 104 + 10% of 104 = 104 + 10.4 = Rs. 114.40.
But present price of the article is Rs. 2288
for 114.4 —> 100 ; 2288 —> ?
Required price = (2288 * 100)/114.4 = 20 * 100 = Rs. 2000.

576. In an election only two candidates contested. A candidate secured 70% of the valid votes and won by a majority of 172 votes. Find the total number of valid votes?
A. 430
B. 570
C. 480
D. 520
E. None of these

Explanation:
Let the total number of valid votes be x.
70% of x = 70/100 * x = 7x/10
Number of votes secured by the other candidate = x – 7x/100 = 3x/10
Given, 7x/10 – 3x/10 = 172 => 4x/10 = 172
=> 4x = 1720 => x = 430.

577. In a class of 140 students, 60% of them passed. By what percent is the number of students who passed more than the number of failed students?
A. 80%
B. 20%
C. 40%
D. 50%
E. None of these

Explanation:
Number of students passed = 60% of 140 = 60/100 * 140 = 84
Number of students failed = 140 – 84 = 56.
Required percentage = 28/56 * 100 = 50%.

578. 40% of Raees marks is equal to 20% of Rahim’s marks which percent is equal to 30% of Rehman’s marks. If Rehman’s marks is 80, then find the average marks of Raees and Rahim?
A. 60
B. 70
C. 80
D. 90
E. None of these

Explanation:
Given, 40% of Ram’s marks = 20% of Rahim’s marks = 30% of Robert’s marks.
Given, marks of Robert = 80
30% of 80 = 30/100 * 8 = 24
Given, 40% of Ram’s marks = 24.
=> Ram’s marks = (24 * 100)/40 = 60
Also, 20% of Rahim’s marks = 24
=> Rahim’s marks = (24 * 100)/20 = 120
Average marks of Ram and Rahim = (60 + 120)/2 = 90

579. Moons salary was first increased by 20% and then decreased by 20%. If his present salary is Rs. 7200, then what was his original salary?
A. Rs. 8000
B. Rs. 7500
C. Rs. 7400
D. Rs. 7200
E. None of these

Explanation:

Let Mohan’s salary be Rs.100.
When increased by 20%, Mohan’s salary = Rs.120
Again when decreased by 20%, Mohan’s salary = 120 – 24 = Rs. 96.
But present salary is Rs. 7200
for, 96 —> 100 ; 7200 —> ?
Required salary is 7200/96 * 100 = Rs. 7500

580. If 25% of x is 15 less than 15% of 1500, then x is?
A. 720
B. 750
C. 820
D. 840
E. None of these

Explanation:
25% of x = x/4 ; 15% of 1500 = 15/100 * 1500 = 225
Given that, x/4 = 225 – 15 => x/4 = 210 => x = 840.