Answer:
d. 20
Step-by-step explanation:
Standard deviation is 4.5
Margin error for the problem is 2 hours
Probability 95%, that means that the siginficance level α is 1 – p
α = 1 – 0.95 = 0.05
margin of error (ME) can be defined as follows
ME = Z(α/2) * standard deviation/ √n
Where n is the sample size
Z(0.05/2) = Z(0.025)
Using a z table Z = 1.96
Now, replacing in the equation and find n
2 = 1.96 * 4.5/ √n
2 = 8.82/√n
√n = 8.82/2
√n = 4.41
n = 4.41^2
n = 19.44 ≈ 20
Answer:
45
Step-by-step explanation:
12 % of the marbles are blue, and
18 % of the marbles are green, so
30 % of the marbles are either blue or green.
There are 150 marbles.
30 % × 150 = 0.30 × 150 = 45
The number of blue or green marbles is 45.
Answer:

Step-by-step explanation:
Given
The attached rhombus
Required
The area
First, calculate the length of half the vertical diagonal (x).
Length x is represented as the adjacent to 60 degrees
So, we have:

Solve for x


So:


At this point, we have established that the rhombus is made up 4 triangles of the following dimensions


So, the area of the rhombus is 4 times the area of 1 triangle




Answer:
a=-20
Step-by-step explanation:
-4(7a+5)=-160
7a+(-20)=-160 Multiply -4 and 5
7a=-140 Subtract -20 from -160
a=-20 Divide 7 by -140