A single di has 6 sides, meaning the probability of rolling a 6 is 1/6. So if you roll a di 18 times you would probably get 6 three times. Meaning the number of unsuccesful rolls would be (18/18 - 3/18). Hope this helps.
First, find the difference between $130 and $104. This equals $26, and to find this discount written as a percent, divide $26 by the original cost of the camera. 26/130=0.2, which represents a 20% discount.
