Answer: 5 seconds
<u>Step-by-step explanation:</u>
Maximum height is the y-value of the vertex. The number of seconds at maximum height is the x-value (aka axis of symmetry).
h(x) = -2x² + 20x + 48
a=-2 b=20 c=48
Axis of symmetry: x = 
= 
= 
= 5
21/7=3mins per wall with 5 people.
Because we assume that all of the people paint at the same rate, 3 X 5=15 mins for one person working alone.
15/3=5 mins per wall with 3 people X 10 people= 50 mins for 3 people to paint 10 walls.
The answer is 50 mins.
8 x 8= 64 so 8 is your answer.
<span>speed = distance/time
total time is 8 hours
outgoing speed is 160 km per hour,
so time = d/160
</span><span>returning speed is 240 km per hour,
so time = d/240
d/160 + d/240 = 8
3d/480 + 2d/480 = 8
5d/480 = 8
5d =480 (8)
5d = 3840
d=3840/5
d=768
answer: so the distance is 768 km</span>
Answer:
Step-by-step explanation:
a) 
Substitute limits to get
= 
Thus converges.
b) 10th partial sum =

=
c) Z [infinity] n+1 1 /x ^4 dx ≤ s − sn ≤ Z [infinity] n 1 /x^ 4 dx, (1)
where s is the sum of P[infinity] n=1 1/n4 and sn is the nth partial sum of P[infinity] n=1 1/n4 .
(question is not clear)