Question

The average weight of a group of 20 students was calculated to be 60 kg, and it was later found that the weight was misread as 80 kg instead of 70 kg. The correct average is
1. 59.5 kg
2. 61 kg
3. 58. 5 kg
4. 59 kg

Answer 1

Correct Answer - Option 1 : 59.5 kg

Given:

Average weight of 20 students = 60 kg

Concept used:

Average is the central value of a given set of values.

Formula Used:

Average = (Sum of Values/Number of Values)

Calculation:

As, the sum of weight of 20 students = 60 kg

Sum of the weight of 20 students = 20 × 60 = 1200 kg

As, it was later discovered that one weight was misread as 80 kg instead of 70 kg.

⇒ Difference = 80 - 70 = 10 kg

Actual sum of the weight of 20 students = 1200 - 10 = 1190 kg

Actual average = 1190/20 = 59.5 kg

∴ The correct average is 59.5 kg.