Question 1195351
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B = Bella's speed in mph
B+5 = Regina's speed in mph


The formula we'll need is:
distance = rate*time
often abbreviated as
d = r*t
The term "rate" is the same as "speed".


If Bella travels for 3 hours at a speed of B mph, then she travels a distance of...
d = r*t
d = B*3
d = 3B
If we knew what B was, then we could find a numeric distance for Bella.


Meanwhile, Regina also travels for 3 hours but at a speed of B+5 mph
d = r*t
d = (B+5)*3
d = 3B+15


Here are their distances:
Bella = 3B
Regina = 3B+15
These distances are in miles.


These two distances must add to 87 miles since this is the gap between them after the three hour mark.
It might help to draw out a number line diagram to visualize what's going on.
Have one person go left, and the other go right.


Bella + Regina = 87
(3B) + (3B+15) = 87
6B + 15 = 87
6B = 87-15
6B = 72
B = 72/6
B = 12
Bella's speed is 12 mph. 
This is comparable to bike speed, though a bit on the slower side. 
Perhaps Bella is riding up a slightly steep hill, or she may be biking at a somewhat leisurely pace not in a hurry to get anywhere.


Regina's speed is B+5 = 12+5 = 17 mph


If you wanted, you can calculate the distances of each person (now that we've determined the value of B). I'll leave that to you for practice. 


<font color=red>Answers:</font>
Bella's speed = 12 mph
Regina's speed = 17 mph
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