# 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 ABILITYExpected questions for Competitive Examinations/ Model QuestionsChoose the correct answer from the options given below:**

- Find the average of first 10 natural numbers?

A. 5

B. 5.5

C. 6 - 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 - Write the next number: 4, 13, 41, 126, ——

A. 164

B. 218

C. 382 - 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 - If 3/7 of a number is 210, find the number?

A. 420

B. 490

C. 560 - If the sum of 7 consecutive numbers is 490. Find the smallest number?

A. 67

B. 70

C. 73 - Find the odd one out: AC, DF, GI, JM

A. DF

B. GI

C. JM - Find the sum of all angles of a polygon of side 15?

A. 2340

B. 2520

C. 2700 - If x: y = 5: 1, xy = 500, find x and y?

A. 25, 20

B. 50, 10

C. 20, 30 - Write as percentage: 0.02

A. 2%

B. 20%

C. 0.2 %

**ANSWERS:**

- 5.5
- 3/10
- 381
- 13
- 490
- 67
- JM
- 2340
- 50, 10
- 2%

**Explanation:**

- Average = Sum of all observations/ Total number of observations

= (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 +10)/10

=55/10 = 5.5 - Multiples of 3 are 3, 6, 9, 12, 15, and 18

Probability = 6/20 = 3/10 - 4

13 = 4 x 3 + 1

41 = 13 x 3 + 2

126 = 41 x 3 + 3

382 = 126 x 3 + 4 - Let age of daughter be y

Mother’s age = 3y

Product = (y) x (3y) = 507

(y) x (y) = 507/3 = 169

y = 13 - Let the number be y

3/7 of y = 210

3y/7 = 210

3y = 210 x 7

y = 490 - 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 - JM
- Sum of all angles of a polygon of n sides = (n – 2) 180degree

= (15 – 2) 180

= 13 x 180

= 2340 - 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 - 0.02 x 100% = (2/100) x 100% = 2%