ashwen venkatesh
Last Activity: 12 Years ago
let the no of students be ''x''
let the amount spent be ''y''
according to question,
x.y=2000 ..............(1)
since five students failed to attend =(x-5)
since the cost increased by rs.20=(y+20)
now the equation (1) becomes
(x-5)(y+20)=2000
xy+20x-5y-100=2000
20x-5y-100=0 [from (1)]
dividing throughout by 5,we get
4x-y-20=0
substitute the value of y from equation (1), i.e., y=2000/x
you will get equation like this
x.x-5x-500=0
when u solve this u wil get,x=25.
and final answer is 25 students attended the picnic