Simple Arithmetic & Mental Ability

Here you can find out practice problems in Mathematics for competitive examinations. It includes Simple Arithmetic and Mental ability questions and study materials for competitive exams.

SIMPLE ARITHMETIC & MENTAL ABILITY
Maths Questions for Competitive Examinations.
Choose the correct answer from the options given below:

1. Find the product of first 5 prime numbers?
   A. 720
   B. 850
   C. 2310
2. Anu bought a watch for 700 rupees and sold it for 644 rupees. Find the loss percentage?
   A. 8.5
   B. 8
   C. 7.5
3. Find the ratio of 5 kg: 500g
   A. 1: 10
   B. 10:1
   C. 1: 100
4. If 10% of a number is 50, find 20% of that number?
   A. 50
   B. 500
   C. 5
5. LCM of 2 numbers is 96 and HCF is 4. If one number is 12, find the other number?
   A. 32
   B. 48
   C. 12
6. If the average of 25, 27, 29 and x is 28. Find the value of x?
   A. 30
   B. 31
   C. 32
7. If the sum of five consecutive numbers is 625, which is the smallest number?
   A. 120
   B. 123
   C. 125
8. If ¼ of a number is 20, find ½ of that number?
   A. 20
   B. 40
   C. 80
9. The number of prime numbers between 1 and 100 is ————–
   A. 23
   B. 25
   C. 27
10. Find the value of 3 x 12 – 5 + 6 x 0 – 1?
    A. 30
    B. 36
    C. 41

Answers with Explanations:

1. 2310
2. 8%
3. 10: 1
4. 500
5. 32
6. 31
7. 123
8. 40
9. 25
10. 30

Explanations:

1. First 5 prime numbers are 2, 3, 5, 7 and 11
   Product = 2 x 3 x 5 x 7 x 11 = 2310
2. Loss% = (loss/CP) x 100 = (56/700) x 100 = 8%
3. 5 kg = 5000g
   5 kg: 500 g = 5000: 500 = 50: 5 = 10: 1
4. Let the number be x.
   10% of x = 50
   Therefore, x = 5000/10 = 500
5. Product of two numbers = LCM x HCF
   One number is 12 and take the other number as y, 12 x y = 96 x 4
   y = (96 x 4)/12 = 32
6. Average = (25 + 27 + 29 + x) / 4 = 28
   (81 + x) = 28 x 4
   81 + x = 112
   x = 112 – 81 = 31
7. Let the 5 consecutive numbers be x, x+1, x+2, x+3 and x+4
   Given x + x + 1 + x + 2 + x + 3 + x + 4 = 625
   5x + 10 = 625
   5x = 625 – 10 = 615
   x =615/5 = 123
8. Let the number be x
   Given ¼ of x = 20
   x = 20 x 4 = 80
   Now ½ of 80 = 40
9. 25
10. 3 x 12 – 5 + 6 x 0 – 1 = 36 – 5 + – 1 = 36- 6 = 30