Question

The average weight of $3$ persons is $65$kg. If a fourth person having a weight of $45$kg joins the group, then what is the average weight of the group?

• A. $65$ kg
• B. $63$ kg
• C. $61$ kg
• D. $60$ kg

Answer 1

The correct option is D $60$ kg

Given:-

Average weight of 3 persons =$65$kg

$\Rightarrow \frac{\text{Total weight of 3 persons}}{3}=65$

$\Rightarrow \text{Total weight of 3 persons}=65\times 3$

$\Rightarrow \text{Total weight of 3 persons}=195$

$\because$ fourth person having a weight of $45$ kg joins the group.

$\therefore$ Total weight of $4$ persons = Total weight of $3$ persons + weight of fourth person

$\therefore$ Total weight of $4$ persons = $195+45=240$

$\Rightarrow \text{Average weight of group}=\frac{\text{Total weight of 4 persons}}{4}=\frac{240}{4}=60kg$