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

The Correct Option is C

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): \(1\)