31) If 40% of 60% of 3/5 of a number is 504, what will be the 25% of 2/5 of that number?

350

150

175

230

Answer: a

Explanation:
Let the number is x.
(40/100) * (60/100) * (3/5) * x = 504
x= 3500
Now, (25/100)*(2/5)* 3500 = 350

32) There are 35 students and 6 teachers in a class, each student gets toffees that are 20% of the total number of students, and each teacher gets toffees that are 40 % of the total number of students. How many toffees were there?

245

405

329

142

Answer: c

Explanation: Solution 1:
Total number of toffees given to students= Number of students * Toffees given to one student
= 35 * 20% of 35
= 35* (20/100) * 35= 245
Total number of toffees given to teachers = Number of teachers * Toffees given to one teacher
= 40 * 40% of 35 = 84
So, total number of toffees = 245+84 = 329 Solution 2:
20 % of 35 = 7 and 40% of 35 = 14
35 students receive = 35*7=245 toffees
6 teachers receive = 6*14=84 toffees
So, Total number of toffees = 245 + 84 = 329

33) If 10% of A's income = 15% of B's income = 20% of C's income. If the sum of their income is 7800, find the income of B.

1800

2400

3000

3600

Answer: b

Explanation:
Let 1% =1
Then, 10% = 10, 15% = 15, and 20% = 20
LCM of 10, 15, and 20 is 60.
The ratio of the incomes of A: B: C = 6:4:3
The sum of the ratio is 13, but ATQ the sum=7800
So, multiply each one with 600
Hence, the income of B = 4*600 = 2400

34) If 50% of (x-y) =30% of (x+y), what percent of x is y?

33.33%

40%

12.25%

25%

Answer: d

Explanation:
(50/100)*(x-y) = (30/100)*(x+y)
(x-y)/2 = (3/10)(x+y)
(x-y) = (3/5) * (x+y)
5x-5y = 3x+3y
2x=8y
y= (1/4) of x
i.e., y is 25% of x.

35) If a number x is 10% less than another number y and y is 10% more than 125, find the value of x.

150

125

123.75

None of these

Answer: c

Explanation:
We can write 10% increase as 11/10 that indicates +1 increase per 10
Similarly, we can write 10% decrease as 9/10 that indicates -1 decrease per 10
So, the required number = 125 * (11/10) * (9/10) = 123.75