Answer:
12/3 = 4
Step-by-step explanation:
Hey!
Hope this helps...
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The first thing we know is that all the answers equal 99, so we cannot cross any answer off, however, what we want to know is what answer (after distribution) looks like 36 + 63...
A.) 11(3 + 6) > 33 + 66
Does 33+66 look like 36+63?
NO
B.) 9(4 + 7) > 36 + 63
Does 36+63 look like 36+63?
YES
C.) 11(4 + 5) > 44 + 55
Does 44+55 look like 36+63?
NO
D.) 3(15 + 18) > 45 + 54
Does 45+54 look like 36+63?
NO
So...
The answer is: B.) 9(4 + 7)
4 feet
Step-by-step explanation:
there's 12 inches in a foot. so 48÷12= 4 feet
<h3>Given</h3>
- a cone of height 0.4 m and diameter 0.3 m
- filling at the rate 0.004 m³/s
- fill height of 0.2 m at the time of interest
<h3>Find</h3>
- the rate of change of fill height at the time of interest
<h3>Solution</h3>
The cone is filled to half its depth at the time of interest, so the surface area of the filled portion will be (1/2)² times the surface area of the top of the cone. The filled portion has an area of
... A = (1/4)(π/4)d² = (π/16)(0.3 m)² = 0.09π/16 m²
This area multiplied by the rate of change of fill height (dh/dt) will give the rate of change of volume.
... (0.09π/16 m²)×dh/dt = dV/dt = 0.004 m³/s
Dividing by the coefficient of dh/dt, we get
... dh/dt = 0.004·16/(0.09π) m/s
... dh/dt = 32/(45π) m/s ≈ 0.22635 m/s
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You can also write an equation for the filled volume in terms of the filled height, then differentiate and solve for dh/dt. When you do, you find the relation between rates of change of height and area are as described above. We have taken a "shortcut" based on the knowledge gained from solving it this way. (No arithmetic operations are saved. We only avoid the process of taking the derivative.)
Note that the cone dimensions mean the radius is 3/8 of the height.
V = (1/3)πr²h = (1/3)π(3/8·h)²·h = 3π/64·h³
dV/dt = 9π/64·h²·dh/dt
.004 = 9π/64·0.2²·dh/dt . . . substitute the given values
dh/dt = .004·64/(.04·9·π) = 32/(45π)
