Question

Some students planned a picnic. The budget for food was $Rs.500$. But $5$ of these failed to go and thus the cost of food for each member increased by $Rs.5$. How many students attended the picnic?

Answer 1

Let number of student be $x$ and the cost for each student be $y.$

According to question:

$xy=500$ ......... (i)

$y=500/x$ ...........(ii)

$(x-5)(y+5)=500$

$xy+5x-5y-25=500$ ....... (iii)

from equation (i),(ii),(iii), we get

$x^2-5x-500=0$

On solving the equation, we get,

$x=25$ and $x=-20$(not possible )

therefore number of student wo attended the picnic $=25-5=20$