# Simple Arithmetic & Mental Ability/ Expected questions for competitive examination.

Simple Arithmetic and Mental Ability is about some model questions that you can expect for competitive examinations. Here you can find out practice problems for GK Maths.

SIMPLE ARITHMETIC & MENTAL ABILITY
Expected questions for Competitive Examinations/ Model Questions
Choose the correct answer from the options given below:

1. Find the average of first 10 natural numbers?
A. 5
B. 5.5
C. 6
2. Find the probability of a number that is randomly selected from numbers 1 to 20 is a multiple of 3?
A. 3/10
B. 5/10
C. 7/10
3. Write the next number: 4, 13, 41, 126, ——
A. 164
B. 218
C. 382
4. The age of daughter is 3 times her mother. Product of their ages is 507. Find the age of daughter?
A. 12
B. 13
C. 14
5. If 3/7 of a number is 210, find the number?
A. 420
B. 490
C. 560
6. If the sum of 7 consecutive numbers is 490. Find the smallest number?
A. 67
B. 70
C. 73
7. Find the odd one out: AC, DF, GI, JM
A. DF
B. GI
C. JM
8. Find the sum of all angles of a polygon of side 15?
A. 2340
B. 2520
C. 2700
9. If x: y = 5: 1, xy = 500, find x and y?
A. 25, 20
B. 50, 10
C. 20, 30
10. Write as percentage: 0.02
A. 2%
B. 20%
C. 0.2 %

1. 5.5
2. 3/10
3. 381
4. 13
5. 490
6. 67
7. JM
8. 2340
9. 50, 10
10. 2%

Explanation:

1. Average = Sum of all observations/ Total number of observations
= (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 +10)/10
=55/10 = 5.5
2. Multiples of 3 are 3, 6, 9, 12, 15, and 18
Probability = 6/20 = 3/10
3. 4
13 = 4 x 3 + 1
41 = 13 x 3 + 2
126 = 41 x 3 + 3
382 = 126 x 3 + 4
4. Let age of daughter be y
Mother’s age = 3y
Product = (y) x (3y) = 507
(y) x (y) = 507/3 = 169
y = 13
5. Let the number be y
3/7 of y = 210
3y/7 = 210
3y = 210 x 7
y = 490
6. Let the 7 consecutive numbers be x -3, x-2, x-1, x, x+1, x+2, x+3
Sum = x – 3 + x- 2 + x – 1 + x + x + 1 + x + 2 + x + 3 = 490
7x = 490
x = 490/7 = 70
Smallest number is x – 3 = 70 – 3 = 67
7. JM
8. Sum of all angles of a polygon of n sides = (n – 2) 180degree
= (15 – 2) 180
= 13 x 180
= 2340
9. Given x:y = 5: 1 and xy = 500
i.e. x/y = 5/1
x = 5y
Substitute the value of x in xy = 500, so we get 5y x y = 500
y x y = 500/5 = 100
y = 10
Therefore, x = 50
So the values of x and y are 50 & 10
10. 0.02 x 100% = (2/100) x 100% = 2%