Let fixed charge = Rs x
Variable charge = Rs y per day
When a student Atakes food for 20 days she has to pay Rs 1000 as hostel charges
So we get
X + 20 y = 1000 …(1)
Subtract 20 y both side we get
X = 1000 – 20 y …(2)
who takes food for 26 days, paysRs 1180 as hostel charges
we get
x + 26 y = 1180
plug the value of x we ge t
1000 – 20 y + 26y = 1180
6y = 180
Y = 180/6 = 30
Plug the value of y in equation second we get
X = 1000 – 20 * 30
X = 1000 – 600
X = 400
Hence fixed charge x = Rs 400
And variable charge y = Rs 30
2 Let fraction is x/y
A fraction becomes 1/3 when 1 is subtracted from the numerator
So that
Cross multiply we get
3x -3 = y …(1)
and it becomes 1/ 4 when 8 is added to its denominator
so that
4x = y + 8
Plug the value of y from equation first we get
4x = 3x – 3 + 8
X = 5
Plug this value back in equation first we get
3*5 – 3 = y
15 – 3 = y
12 = y
Hence fraction is x/y = 5/12