# Kerala PSC GK | Practice/Model Maths Questions - 7

1. The average age of husband and his wife was 23 years at the time of their marriage. After 5 years they have a one year old child. The average age of the family now:
[a] 19 years
[b] 23 years
[c] 28.5 years
[d] 29.3 years

Sum of ages of husband and wife = 23x2=46
After 5 years, sum of ages of husband and wife = 46+10=56
The sum of ages including child = 56+1=57
Average = 57/3 = 19 years

2. What is 90% of 90% of 100?
[a] 63
[b] 72
[c] 81
[d] 90

90/100 x 90/100 x 100 = 81

3. 10% of x is 25% of y then x:y is:
[a] 5:2
[b] 2:5
[c] 1:2
[d] 2:1

(10/100)x = (25/100)y
x/100 = y/4
x/y = 10/4 = 5/2
x:y = 5 : 2

4. If 45% of students in a school are boys and number of girls is 1100. Find out the number of boys
[a] 900
[b] 1500
[c] 1350
[d] 2000

100 - 45% = 55% girls = 1100
Total Students
1100/55 x 100 = 2000
Number of boys
2000 - 1100 = 900

5. 15% of 40 is greater than 25% of a number by 2, the number is
[a] 13
[b] 14
[c] 15
[d] 16

15% of 40 = 6
25% = 6 - 2 = 4
100% = 4 x 100 / 25 = 16

6. If an examination 86% of the candidates passed and 224 failed. How many candidate appeared for the exam?
[a] 800
[b] 1540
[c] 1600
[d] 3136

Failed candidates = 100 - 86 = 14%
Total = 224/14 x 100 = 1600

7. In an election between two candidates the candidate who secure 30% votes is defeated by 4360 votes. Find the number of votes secured by winning candidate.
[a] 7490
[b] 7630
[c] 7080
[d] 7070

vote collected by other candidate = 100-30=70%
∴ 70% - 30% = 40% = 4360
Total votes = 4360/40 x 100 = 10900
Total votes secured by winning candidate
10900 x 70/100 = 7630

8. If the radius of a circle is increased by 50% the perimeter of the circle will be increased by
[a] 20%
[b] 30%
[c] 40%
[d] 50%

Let radius be r, Perimeter = 2πr
If radius increased 50%, r + r/2 = 3r/2
Perimeter = 3πr
3πr - 2πr = πr
%change = πr/2πr x 100 = 50%

9. A man spends 89% of his monthly income. If he saves Rs. 2244 per month. What is his monthly income
[a] 20400
[b] 22440
[c] 24000
[d] 18156

Savings = 100-89=11% = 2244
Salary = 224/11 x 100 = 20400

10. A student has to secure 35% marks to pass the exam. If he get 100 marks and fails by 40 marks. The maximum marks.
[a] 300
[b] 250
[c] 400
[d] 350

Maximum marks = 100(100+40)/35
100x140/35 = 100x4=400