Question

One adult and $10$ children are in an elevator. If the adult's weight is $4$ times the average (arithmetic mean) weight of the children, then the adult's weight is what fraction of the total weight of the $11$ people in the elevator?

• A. $\frac{2}{7}$
• B. $\frac{3}{7}$
• C. $\frac{4}{7}$
• D. None of the above

Answer 1

The correct option is A $\frac{2}{7}$

Let $x$ be the average mean weight of a children.

$\therefore$ weight of 10 childrens $=10x$

$\therefore$ weight of a adult $=4x$

$\Rightarrow$ Total weight $=10x+4x=14x$

Adult weight as a fraction of total weight $=\frac{4x}{14x}=\frac{2}{7}$

Hence, option $A$ is correct.