Question

There are three persons A B, and C in a room. If a person D joins the room, the average weight of the persons in the room reduces by x kg . Instead of D , if person E joins the room, the average weight of the persons in the room increases by 2 kg x . If the weight of E is 12 kg more than that of D , then the value of x is

• A. 1.5
• B. 0.5
• C. 1
• D. 2

Answer 1

Answer: (C)

1

Answer 2

Let $A, B, C, D$ and $E$ weights are $a, b, c, d$ and $e$.
According to the ques,
$\frac {a+b+c}{3}-\frac {a+b+c+d}{4}=x$ ……… (i)

$\frac {a+b+c+e}{4}-\frac {a+b+c}{3}=2x$ ……… (ii)

Eq (i) + Eq (ii),
$\frac {a+b+c}{3}-\frac {a+b+c+d}{4}+\frac {a+b+c+e}{4}-\frac {a+b+c}{3}=x+2x$

$\frac {e-d}{4}=3x$
$e-d = 12x$
$12x=12$
$x=1$

So, the correct option is (C): $1$