Question

The average weight of three men $A,B$ and $C$ is $84$ $kg.D$ joins them and the average weight of the four becomes $80$ $kg.E,$ whose weight is $3kg$ more than that of $D,$ replaces $A.$ Now the average weight of $B,C,D$ and $E$ becomes $79$ $kg,$ then the weight of $A$ is

• A. $65kg$
• B. $70kg$
• C. $75kg$
• D. $80kg$

Answer 1

The correct option is C $75kg$

Sum of weight of $A,B$ and $C=3\times 84=252$

Weight of $D=4\times 80-252=320-252=68$kg

Weight of $E=68+3=71$kg

Sum of $A+B+C+D=320$ ....(1)

$B+C+D+E=4\times 79=316$ .....(2)

Subtracting (2) from (1)

$A-E=4$

$A-71=4$

$\Rightarrow A=75$kg

Option C is correct.