Question
Tue February 26, 2013 By:
 

Some students arranged a picnic. The total budget is rs 240. because 4 students of the group failed to go the cost of food for each student increased by rs 5. How many students went to the picnic?

Expert Reply
Tue February 26, 2013
Let the number of students be x and cost per sudent y
 
So, xy = 240 i.e. y = 240/x
Also, since 4 students failed to go resulting in the increase of cost by Rs 5
 
(x-4) (y+5) = 240
xy + 5x - 4y -20 = 240
240 + 5x - 4*240/x - 20 = 240
5x2 - 20x - 960 = 0
x2 - 4x - 192 = 0
(x-16) (x+12) = 0
x = 16 or x = -12
 
Since, x can't be negative, hence, x = 16. 
 
So, the number of the students who went to picnic = x-4 = 12.
 
Home Work Help