Question

Out of $9$ persons, $8$ persons spent Rs. $30$ each for their meals. The ninth one spent Rs. $20$ more than the average expenditure of all the nine. The total money spent by all of them was:

• A. Rs. $260$
• B. Rs. $290$
• C. Rs. $292.50$
• D. Rs. $400.50$

Answer 1

The correct option is C Rs. $292.50$

let $9^{th}$ person spent 'x' rupees

Then As per Question

$x=20+\frac{(30+30+---8times)+x}{9}$

$\Rightarrow x-20=\frac{240+x}{9}$

$\Rightarrow 9x-180=240+x$

$\Rightarrow 8x=420$

$\Rightarrow x-\frac{420}{8}$

$x=52.5$

Hence, Total money spent = 240+52.5

= 292.5