Do you have a picture would probably make more sense if you added one
Answer: 3) 772.5 kg
Step-by-step explanation: That's what I got and I'm 100% sure that's the answer
Answer:
After 3 seconds
Step-by-step explanation:
Given

Required
Seconds to attain maximum height
The maximum of a quadratic function
is calculated using:

So, we have:

Where:
and 
So:


Cancel out negatives


Answer:
Step-by-step explanation:
western beach: y = -2x + 100
dunes beach : y = 5x + 20
set the equations equal to each other
-2x + 100 = 5x + 20
100 - 20 = 7x
80 = 7x
80/7 = x
x ~ 11.43 years