Answer:
-1/4 meter per minute
Step-by-step explanation:
Since, the volume of a cube,

Where, r is the edge of the cube,
Differentiating with respect to t ( time )

Given, 
Also, V = 8 ⇒ r = ∛8 = 2,
By substituting the values,



Hence, the rate of change of an edge is -1/4 meter per minute.
After the 25% discount the vase would cost $18.00
For this problem, let x be the number of children and y for adults. Formulate the equations: 1st equation, x + y = 3,200 and 2nd equation 5x + 9y = 24,000. Re-arrange 1st equation into x = 3200 - y. Then, substitute into 2nd equation, 5(3,200-y) + 9y = 24,000. Then, solve for y. The 16,000 - 5y + 9y = 24000. Final answer is, y = 2000 adults went to watch the movie.