Answer:
The time taken for the flare to hit the ground is approximately 10.7 seconds.
Step-by-step explanation:
Given : Suppose a flare is shot from the top of a 120 foot building at a speed of 160 feet per second. The equation
models the h height at t seconds of the flare.
To find : How long will it take for the flare to hit the ground?
Solution :
The equation
models the h height at t seconds of the flare.
The flare to hit the ground when h=0.
Substitute in the equation,

Applying quadratic formula, 
Where, a=-16, b=160 and c=120





Reject the negative value.
Therefore, the time taken for the flare to hit the ground is approximately 10.7 seconds.
Answer:
4 mph
Step-by-step explanation:
Let :
Boat speed = 20 mph
speed of current = x mph
Distance against current = 2 miles
Distance with current = 3 miles
speed against current will be ; 20 - x
speed with current will be ; 20 + x
Time =distance / speed against time against = time with current
Solving Mathematically ;
2/(20-x )=3/(20 +x)
2(20+x )= 3( 20-x )
40+2x = 60-3x
3x +2x=20
5x=20
x = 20 / 5
x = 4 mph
Speed of current = 4 mph
X=-8
Х/2 - x = x/4 + 6
1/2x - x = 1/4x + 6
-1/2x=1/4x+6
-2x=x+24
-2x-x=24
-3x=24
X=-8