7.50 dollars because per each mile its $2.50 . and $2.50 times 3 equals $7.50
Here is the equation:

Since both decimals are negative, the answer will be positive.
- Negative times Negative = Positive
Divide both sides by -3.9 to leave the variable alone:

r is equal to 4 → r = 4
Answer: See explanation
Step-by-step explanation:
You didn't give the options but let me help out.
First, we need to convert 2 2/3 hours to minutes. This would be:
= 2 2/3 × 60 minutes
= 8/3 × 60 minutes
= 160 minutes
Since water goes over a waterfall at a rate of 162 1/2 gallons every 15 minutes. The the gallons of water going over the waterfall in 2 2/3 hours would be:
= (162 1/2 × 2 2/3hours) / 15 minutes
= (162 1/2 × 160) / 15
= 1733 1/3 gallon
The height of the fence is irrelevant. The bottom of the ladder is 3+8 = 11 feet from the building. The window is 14ft above the ground:
sqrt(14^2+11^2) = length of your ladder.
The expressions 100×10 and the more complicated
(100 - 4a)(10 + a)
are calculating annual (expected) revenue. In 100×10 the 100 is the number of decks and the 10 is the price per deck. In (100 - 4a)(10 + a) the 100-4a is the number of decks and the 10+a is the price per deck. So a must be the amount the price increases.
Answer: amount of price increase, last choice