Question

The average income of A for $15$ days is $Rs.70$. The average for the first five days is $Rs.60$ and that for the last nine days is $Rs.80$. His income for the sixth day is

• A. $Rs.80$
• B. $Rs.60$
• C. $Rs.40$
• D. $Rs.30$

Answer 1

Answer: (D)

$Rs.30$

$\Rightarrow$ The average income of $A$ for $15$ days is $Rs.70$.

$\therefore$ Total income of $15$ days $=15\times Rs.70=Rs.1050$

$\Rightarrow$ The average income of first five days is $Rs.60$

$\therefore$ Total income of first $5$ days $=5\times Rs.60=Rs.300$

$\Rightarrow$ The average income of last nine days is $Rs.80$

$\therefore$ Total income of last $9$ days $=9\times Rs.80=Rs.720$

$\Rightarrow$ $A^{\prime }s$ income for $6th$ day $=$ Total income of $15$ days $-$ Total income of first $5$ days $-$ Total income of last $9$ days.

$=Rs.1050-Rs.300-Rs.720$

$=Rs.30$

$\therefore$ $A^{\prime }s$ income for $6th$ day is $Rs.30$.