Some students planned a picnic. The total budget for food was Rs. 2000. But, 5 students failed to attend the picnic and thus the cost for food for each member increased by Rs. 20. How many students attended the picnic and how much did each student pay for the food?
Let x be the number of students who planned picnic
Original cost of food for each member = 
5 students failed to attend the picnic, so (x – 5) students attended the picnic
New cost of food for each member = 
According to the question
taking LCM
x2 – 5x = 500 cross multiplying
x2 – 5x – 500 = 0
Using the splitting middle term – the middle term of the general equation 
is divided in two such values that:
Product = a.c
For the given equation a = 1 b = – 5 c = – 500
= 1. – 500 = – 500
And either of their sum or difference = b
= – 5
Thus the two terms are – 25 and 20
Sum = – 25 + 20 = – 5
Product = – 25.20 = – 500
x2 – 5x – 500 = 0
x2 – 25x + 20x – 500 = 0
x(x – 25) + 20(x – 25) = 0
(x + 20) (x – 25) = 0
(x + 20) = 0 or (x – 25) = 0
x = – 20 or x = 25
x cannot be negative thus x = 25
The number of students who planned picnic = x – 5 = 25 – 5 = 20
Cost of food for each member = 