Answer:

Step-by-step explanation:
1st boat:
Parabola equation:

The x-coordinate of the vertex:

Equation:

The y-coordinate of the vertex:

Parabola passes through the point (-8,1), so

Solve:

Parabola equation:

2nd boat:
Parabola equation:

The x-coordinate of the vertex:

Equation:

The y-coordinate of the vertex:

Parabola passes through the point (-8,1), so

Solve:

Parabola equation:

System of two equations:

Easy peasy
the average rate of change in section A is the slope from (1,g(1)) to (2,g(2))
the average rate of chagne in section B is the slope from (3,g(3)) to (4,g(4))
A.
section A
g(1)=4(3)^1=12
g(2)=4(3)^2=4(9)=36
slope=(36-12)/(2-1)=24/1=24
section B
g(3)=4(3)^3=4(27)=108
g(4)=4(3)^4=4(81)=324
slope=(324-108)/(4-3)=216/1=216
section A has an average rate of change of 24
section B has an average rate of change of 216
84% of 50 is 42. So if your test was graded out of 50 you would've gotten 42/50. If you multiply 50 by 2 (50x2), you have 100, so then you'd just divide the 84% by 2 so you'd get 42%