Answer:
dv = surface area * dh
so
dv/dt = surface area * dh/dt
width at surface = 40 + (80-40)(30/40)
= 40 + 30 = 70 cm = 0.70 m
so
surface area = 9 * .7 = 6.3 m^2
so
.3 m^3/min = 6.3 m^2 * dh/dt
and
dh/dt = .047 meters/min or 4.7 cm/min
Step-by-step explanation:
I drew it out. Hope this helps.
Draw a straight, horizontal line. Mark evenly-spaced scale divisions, 0 to 5 (because all of the given numerals fit within this domain).
Recognize that the LCD of these fractions and mixed numbers is 6.
Convert all of the given fractions to denominator 6, as needed (some already have that denominator).
Arrange the resulting fractions in ascending order. For example, 5/6, 1/6, 3/6 would become 1/6, 3/6, 5/6 (in ascending order).
Plot all your numerals (all of which have denominator 6) on your number line.
The equation of the vertical line passing through point -4,7 would be X = -4.
