Average

What you'll learn

What an average really is, the one formula, and the 'work with the total' trick for tricky problems.

This chapter has

Average — solved practice questions

6 SSC / Banking Quantitative Aptitude questions with step-by-step solutions. Attempt each, then reveal the answer.

1. Q1easy

   What is the average of 10, 20 and 30?

   • A15
   • B20
   • C25
   • D30
   Show answer & solution

   Correct answer: (B) 20

   Average = sum ÷ count = (10 + 20 + 30) / 3 = 60/3 = 20.

2. Q2easy

   What is the average of the first 5 natural numbers (1, 2, 3, 4, 5)?

   • A2.5
   • B3
   • C3.5
   • D4
   Show answer & solution

   Correct answer: (B) 3

   Sum = 15, count = 5, average = 15/5 = 3.

3. Q3easy

   The average of 5 numbers is 20. What is their sum?

   • A80
   • B100
   • C120
   • D125
   Show answer & solution

   Correct answer: (B) 100

   Sum = average × count = 20 × 5 = 100.

4. Q4hard

   The average age of 5 students is 12 years. When the teacher's age is included, the average becomes 15 years. Find the teacher's age.

   • A25
   • B30
   • C35
   • D40
   Show answer & solution

   Correct answer: (B) 30

   Students' total = 5 × 12 = 60. With teacher (6 people) total = 6 × 15 = 90. Teacher's age = 90 − 60 = 30.

5. Q5easy

   What is the average of 2, 4, 6, 8 and 10?

   • A5
   • B6
   • C7
   • D8
   Show answer & solution

   Correct answer: (B) 6

   Sum = 30, count = 5, average = 30/5 = 6.

6. Q6medium

   A batsman scores 60, 70 and 80 runs in three innings. What is his average score?

   • A65
   • B70
   • C75
   • D80
   Show answer & solution

   Correct answer: (B) 70

   Average = (60 + 70 + 80)/3 = 210/3 = 70.

Want the full set? Practise all 6 Average questions →