Let volleyball be v and let basketball be b.
v : b = 4 : 7, b = 21
v : 21 = 4 : 7
v/21 = 4/7
7*v = 4*21
v = 4*21/7
v = 4*3
v = 12
Volleyballs are 12
Hope this helps.
Answer:
Step-by-step explanation:
Area of the figure = Area of rectangle with dimensions 16 in and 4 in + Area of two right triangles with base (7 - 4 = 3) 3 in and height 8 in

Answer:
3.4
Step-by-step explanation:
Standard deviation of a population is defined as:
σ² = ∑(xᵢ − μ)² / n
The standard deviation of a sample is defined as:
s² = ∑(xᵢ − x)² / (n - 1)
It's not clear which one we have, so let's calculate both.
First, we must find the mean.
μ = (5+12+15+10+12+6+8+8) / 8
μ = 9.5
Now we find the squares of the differences:
(5-9.5)² + (12-9.5)² + (15-9.5)² + (10-9.5)² + (12-9.5)² + (6-9.5)² + (8-9.5)² + (8-9.5)²
= 80
Divide by n:
σ² = 80 / 8
σ² = 10
And take the square root:
σ = √10
σ ≈ 3.2
That's not one of the answers, so let's try the standard deviation of a sample instead of a population.
Instead of dividing by n, we'll divide by n-1:
s² = 80 / 7
And take the square root:
s = √(80/7)
s ≈ 3.4
So that must be it.
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