Question

The average age of 5 men is the same as it
was 3 years ago, because one old member was
replaced by a new member. Find the difference
in the ages of the old member and new members.​

Answer 1

$\bold \color{navy} Correct \: Answer:$

$\bf \huge \color{red}15 \: years$

$\bf \color{navy}Description \: for \: Correct \: answer:$

$\bf \: Let \: the \: present \: average \: is = x \: years</p><p>$

$\bf \: Total \: age = 5x \: year$

$\bf \: According \: to \: the \: question,$

$\bf \: 5x - y + z = 5x - 15$

$\bf \: where \: y = Replaced \: member$

$\bf \: z = New \: member$

$\bf - y + z = - 15$

$\bf \: y - z = 15$

$\bf This \: is \: the \: required \: difference.$

$\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \tt \huge \color{teal}(Or)$

$\bf \: Let \: x \: be \: age \: before \: 3 \: year$

$\bf \: So \: average \: age \: before \: replacement \: x+3$

$\bf \: Let \: y \: be \: new \: age \: after \: replace$

$\bf \: Y=x+3$

$\bf \: Y-x = 3$

$\bf \: Since \: average \: of \: 5$

$\bf \: So \: 5 \times 3=15$

$\bf \: Total \: age \: replaced \: will \: be \: 15 \: years.$

$\bf \: So \: new \: team \: is \: 15 \: younger \: than \: old.$

$\huge \tt \color{deeppink} Hope \: I \: am \: rightツ$