Answer:
a) 
b)
Explanation:
Let´s use Doppler effect, in order to calculate the observed frequency by the byciclist. The Doppler effect equation for a general case is given by:

where:





Now let's consider the next cases:




The data provided by the problem is:

The problem don't give us aditional information about the medium, so let's assume the medium is the air, so the speed of sound in air is:

Now, in the first case the observer alone is in motion towards to the source, hence:

Finally, in the second case the observer alone is in motion away from the source, so:

<em>L</em><em>ike the alto in a choir the octavina plays the lower melody . what musical element does this tell?</em>
answer : melody....
Answer:
Who is moving the fastest: Green triangle
What is the slope of Blue Diamonds: 5/6 or 5/7, can’t tell completely
<h2><u>
Hope This helped!</u></h2>