Yes it is. 5\7 is a fraction, therefore it is rational; it can be written as a decimal, 0.714285...... [bar notation indication].
To find the total people, divide the number of people that made a purchase by the percentage:
45 / 0.30 = 150 people entered.
It will be $27.45 with 55 percent off.
I'm certain up until the reflection. after that there's some guess work just fyi