Answer:
1.725 mph
There are 5280 feet in a mile, so you divide by that and get 12.075. Since it's seven hours, you divide by 7 and get 1.725.
The nurse is using Deductive reasoning.
Deductive reasoning is a valid form of proof. Here, a person makes conclusions based on previously known facts. It is process of reasoning from one or more statements to reach a logically certain conclusion. If all the parameters are true and the terms are clear then the conclusion reached is necessarily true.
Answer:
Refer to the attachment 
Step-by-step explanation:
<h3><u>Diagram</u><u>:</u><u>-</u></h3>

<h3><u>Note</u><u>:</u><u>-</u></h3>
View the ans from Web for complete diagram.
Answer:
-21k=7(-3k)................………………
For 12, you would do 90=4x+42, and 48=4x, and x=12
for 15, you would do 90=8x+66, and 24=8x, and x=3
for 18, you would do 90=3x+57, and 33=3x, and x=11