Question 939056
Let x be the cost of TV before sale
In sale,cost=£90
25% off on price
Off  on price=25%of x
  ={{{(25/100)*x}}}
=0.25 x
Hence x-0.25x=90
   X(1-0.25)=90
X(0.75)=90
Divide with 0.75 on both sides
{{{x*0.75/0.75=90/0.75}}}
X=120
Result:price before sale(x)=£120