Answer:
Please post one by one answer
A stuntman jumping off a 20-m-high building is modeled by the equation h = 20 – 5t2, where t is the time in seconds. A high-speed camera is ready to film him between 15 m and 10 m above the ground. For which interval of time should the camera film him?
Answer:

Step-by-step explanation:
Given:
A stuntman jumping off a 20-m-high building is modeled by the equation
-----------(1)
A high-speed camera is ready to making film between 15 m and 10 m above the ground
when the stuntman is 15m above the ground.
height
Put height value in equation 1





We know that the time is always positive, therefore 
when the stuntman is 10m above the ground.
height
Put height value in equation 1







Therefore ,time interval of camera film him is 
We know that
speed=distance/time
solve for time
time=distance/speed
in this problem
<span>Marco runs at a rate of 6 miles per hour.
</span><span>Fernando funs at a rate of 7.2 miles per hour
Difference=7.2-6=1.2 miles/hour
so
speed=1.2 miles/hour
distance=0.3 miles
time=?
</span>time=distance/speed-----> 0.3/1.2-----> 0.25 hour-----> 0.25*60=15 minutes
<span>
the answer is
0.25 hour (15 minutes)
Alternative Method
Let
x---------> Fernando's distance when Marco is 0.3 miles apart
</span>Fernando funs at a rate of 7.2 miles per hour
<span>for distance =x
time=x/7.2------> equation 1
</span>Marco runs at a rate of 6 miles per hour.
for distance=x-0.30
time=(x-0.30)/6------> equation 2
equate equation 1 and equation 2
7.2*(x-0.3)=6x-----> 7.2x-2.16=6x
7.2x-6x=2.16------> x=2.16/1.2-------> x=1.8 miles
time=x/7.2-----1.8/7.2=0.25 hour
Answer:
<h2>2 in each box of course</h2>
g= green chips r= red chips
3 boxes of green chips meaning for each box there are <em>2</em> chips so there are 6 green chips. 5 boxes of red chips meaning for each box there are two chips so there are 10 red chips and 6 g + 10r = 16 chips in total
Step-by-step explanation:
Answer:
x + 2y = 4
x − y = − 3
x − y =9 , x + y=6
x + y =4,
x− y =2
Step-by-step explanation: