Ok ok so I saw that someone else had given you an answer but I thought it might be best if you got an explanation to go with it.
Basically to know what your final price is you need to know what percentages represent.
Since they are simply parts of a whole (because you know 100% of something is a whole) we can look them as fractions like 40/100 in this case.
Then we can multiply 39.00 by 40/100 or 0.40 in decimal form and get 15.60.
It’’s important to remember that this 15.60 is just what 40%of 39 is so we still need to subtract it from our total to get the sales price.
39-15.60=23.40
So $23.40 is the sales price
Hope this helps!
Answer:
Yes
Step-by-step explanation:
13(10) + 15(1) 
130+15 
145
← Yes it is
Answer:
B.
Step-by-step explanation:
(-7x + 4)(-7x - 4)
= 49x^2 - 28x + 28x - 16
= 49x^2 - 16.
Answer:
5 in.
Step-by-step explanation:
The ratio of map distance to real distance is 1 in : 3 km meaning that 1 inch on the map describes 15 km in real life.
15 km is 5 times 3 km, so the map distance is 5 times 1 in., or 5 in.
1 in. x 5 : 3 km x 5
This is a "school math" problem where things come out nicely! Another way to look at this is with equivalent fractions.

"cross multiply"

Answer:
8 gallons of gasoline costs $30.63.
Step-by-step explanation:
Set up a proportion to solve for x, or the cost of 8 gallons of gasoline. The $47.86 goes on top of the first ratio, and 12.5 goes on top of the second. This is because the $47.86 is the cost of the 12.5 gallons of gasoline. Next, put x on the bottom of the first ratio and 8 on the bottom of the second ratio. This is because the amount of money you are trying to find, x, is the cost of the 8 gallons of gasoline. The proportion should look like this: 
To solve the proportion, use cross multiplication. To do that, multiply 8 by 47.86 to get 382.88. Then, divide 382.88 by 12.5. The answer is 30.6304, so round to the nearest cent to get a total of $30.63.
I hope this helps! ☺