Answer:
the temp was at least 65 degrees or 66 degrees.
Step-by-step explanation:
(1) let there be x book and let the total cost be y dollars.
y=19.25x+40
y=16x+69.25
(2) 19.25x+40=16x+69.25
3.25x=29.25
x=9
9 silver book, 9 gold book.
(3) y=19.25x+40=19.25*9+40=213.25 dollars
both companies' total cost are 213.25 dollars.
Subtract it so that you can get your answer
The answer is the temperature goes down 2.8° every hour and the expression is x=-11.2/4 because 4 is how many hours between 6pm and 10pm and its -11.2 because that was how much the temperature dropped from 6pm to 10pm