Question

The average marks of Ravi in five subjects are 150, but in mathematics 43 was misread as 23 during the calculation. The correct average is:

• A. 154
• B. 150
• C. 160
• D. 148

Answer 1

Answer:

A. 154

Solution: Given: The average marks of Ravi in five subjects are 150 In mathematics 43 was misread as 23 Formula Used: Average = (Sum of total numbers)/Total numbers Error in marks = Original marks - Wrong marks Calculation: Sum of marks in all subjects = 150 × 5 ⇒ Sum of marks in all subjects = 750 Now, error in marks = 43 - 23 ⇒ Error in marks = 20 Now, these 20 marks must be added to the sum of marks ⇒ New sum of marks = 750 + 20 = 770 New average = 770/5 ⇒ New average = 154 ∴ The actual average is 154. Shortcut Trick : Deflection in the total = 43 - 23 = 20 Deflection in the average = 20/5 = 4 ⇒ The new average = 150 + 4 = 154 ∴ The actual average is 154.