78×.33=25.74 busses are new
25.74+15=40.74 new busses
78+15=93 total busses
40.74/78=0.5223076923= 52% will be new with the new 15 busses
If you want to multiply the two functions, the answer is a.
In fact, you have

Answer:
6:1
Step-by-step explanation:
1 hr= 60 minutes
60 minutes= 3600 seconds
3600:600
36:6
Answer:
28.26 
Step-by-step explanation:
The radius is half of the diameter. 6/2 = 3, so the radius of this circle is 3 cm.
The formula for the area of a circle is: π
Plugging 3 into the radius, we have:
× π =
9 × π
We can round π to 3.14
9 × 3.14 = 28.26