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- Quantitative Aptitude
The average monthly expenditure of a family for the first four months is $Rs.\,2750$ for the next three months is $Rs.\,2940$ and for the last five months is $Rs.\,3130.$ If the family saves $Rs.\,5330$ throughout year, find the average monthly income of the family for that year. (in $Rs.$)
$3800$
$3500$
$3400$
$4200$
Solution
Average monthly expenditure of $4$ months $=22700$
Total expenditure for $4$ months $=Rs.\, 2700 \times 4$
$=Rs.\, 11000$
Average monthly expenditure of $3$ months
$=Rs.\, 2940$
Total expenditure for $3$ months $=$ $2940$ $\times 5$
$=Rs.\, 8820$ ….$(1)$
Average monthly expenditure of $5$ months $=Rs.\, 3130$
Total expenditure of $5$ months $=Rs.\, 31020$
$=Rs.\, 1560$…$(2)$
Total expenditure in the whole year
$=Rs.\, 11000+8820+215650=Rs.\, 35470$
Saving during the whole year $=Rs.\, 5330$
Total income of the family during the year
$=Rs.\, 35470+\text { ₹5330 }=Rs.\, 40800$
$\therefore$ Average monthly income during the year
$=\frac{40800}{12}=Rs.\, 3400$
