Saidhari bought a toaster oven for $90 this price was 1/4 off the list price. what was the list price

The information's given in the question are of vital importance. Based on those information's the answer to the question can be easily deduced. The price at which Saidhari bought the toaster oven is 1/4th off the list price.
Price at which Saidhari  bought a toaster oven = $90
Let us assume the list price = x
then
3x/4 = 90
3x = 90 * 4
  x = 360/3 dollar
   = 120 dollar
So the list price of the toaster oven bought by Saidhari is $120. I hope this is the answer you were looking for. The procedure should be clear enough for you to understand as well.

1/4 of the list price was off, so $90 was 3/4 of the list price. (1 -1/4= 3/4).

We have an equation: 90/? = (3/4)/1

Cross multiply:
3/4*? = 90*1
⇒ ?= 90*1/(3/4)= 90*1* (4/3)= 120.

The list price was $120.

Hope this helps~