Answer:
A,B,D
Step-by-step explanation:
Answer:
t = 2.52 seconds
Step-by-step explanation:
h=139-15t-16t^2
We want to know when the ball hits the ground
That would be when h=0
0 = 139-15t-16t^2
We can use the quadratic formula to find t
t = -b ± sqrt(b^2-4ac)
----------------------
2a
where a = -16 b = -15 and c = 139
t = -(-15) ± sqrt((-15)^2-4(-16)139)
----------------------
2(-16)
t = (15) ± sqrt(225+8896)
----------------------
-32
t = (15) ± sqrt(9121)
----------------------
-32
t = 15+ sqrt(9121) t = 15- sqrt(9121)
-------------------- or -------------------
-32 -32
-3.453247707 or 2.515747707
Since time cannot be negative
2.515747707
Round to the nearest hundredth
t = 2.52 seconds
4/5 of x -3/4 of x =5
solution by LCM
16x-15x/20 =5
x/20 =5
x=100
<span>answer 100</span>
Step-by-step explanation:
9x - 2 = 4x + 8 → (9-4)x = 8 + 2 → 5x = 10 → x = 10/2 = 5
C. multiplication
Multiplication not used
Let V, be the rate in still water and let C = rate river current
If the boat is going :
upstream, its rate is V-C and if going
downstream, its rate is V+C,
But V = 5C, then
Upstream Rate: 5C - C = 4 C
Downstream rate: 5C+C = 6C
Time = distance/Rate, (or time = distance/speed) , then:
Upstream time 12/4C and
Downstream time: 12/.6C
Upstream time +downstream time:= 2h30 ' then:
12/4C + 12/.6C = 2.5 hours
3/C + 2/C = 5/2 (2.5 h = 5/2)
Reduce to same denominator :
5C = 10 and Rate of the current = 2 mi/h
