I think i’m not really good at math so..
D.
(7,-3) and (4,0)
Answer:
<u>The equations for each function:</u>
- A(t) = 60 - 6t
- B(t) = 42 - 3t
<em>The lines plotted, see attached</em>
<u>The point at which both the snowmen have same height:</u>
- 60 - 6t = 42 - 3t
- 6t - 3t = 60 - 42
- 3t = 18
- t = 6
<u>The required interval is </u>
Answer: -8+61 = 53 and 6+61 = 67
Check the picture below. Recall, is an open-top box, so, the top is not part of the surface area, of the 300 cm². Also, recall, the base is a square, thus, length = width = x.

so.. that'd be the V(x) for such box, now, where is the maximum point at?

now, let's check if it's a maximum point at 10, by doing a first-derivative test on it. Check the second picture below.
so, the volume will then be at
5(2x - 4) = 45
10x - 20 = 45
10x = 45 + 20
10x = 65
x = 65/10 reduces to 13/2 or 6 1/2