Question

A group of friends goes for dinner and gets bill of rs 2400. Two of them says that they have forgotten their purse so remaining make an extra contribution of rs 100 to pay up the bill. Tell the no. Of person in that group.

Answer 1

Answer:

8

Step-by-step explanation:

x*y =2400 i.e. x=2400/y (x number of ppl &y amount paid per person)

(x-2)(y+100)=2400

xy-2y+100x-200=2400

2400-2y+100x-200=2400 (since xy=2400)

100x-200-2y=0

100x-200-2*2400/x=0 (since y=2400/x)

100(x-2-48/x)=

x^2-2x=48

x(x-2)=48

The equation is valid on substituting value of x with 8

Hence the group contains 8 members