Answer:


Step-by-step explanation:
By geometric mean property:

Answer:
or 
Step-by-step explanation:
Given



Required
Determine the probability of selecting Black and Red
First, we need to calculate the number of red and black balls
The probability is calculated as thus:

Convert to mathematical expressions
![Probability = [P(Black) *P(Red)] + [P(Red) *P(Black)]](https://tex.z-dn.net/?f=Probability%20%3D%20%5BP%28Black%29%20%2AP%28Red%29%5D%20%2B%20%5BP%28Red%29%20%2AP%28Black%29%5D)
Solve for each probaility;


So, we have:
![Probability = [P(Black) *P(Red)] + [P(Red) *P(Black)]](https://tex.z-dn.net/?f=Probability%20%3D%20%5BP%28Black%29%20%2AP%28Red%29%5D%20%2B%20%5BP%28Red%29%20%2AP%28Black%29%5D)
![Probability = [\frac{25}{100} *\frac{40}{100}] + [\frac{40}{100} *\frac{25}{100}]](https://tex.z-dn.net/?f=Probability%20%3D%20%5B%5Cfrac%7B25%7D%7B100%7D%20%2A%5Cfrac%7B40%7D%7B100%7D%5D%20%2B%20%5B%5Cfrac%7B40%7D%7B100%7D%20%2A%5Cfrac%7B25%7D%7B100%7D%5D)
![Probability = [\frac{1000}{10000}] + [\frac{1000}{10000}]](https://tex.z-dn.net/?f=Probability%20%3D%20%5B%5Cfrac%7B1000%7D%7B10000%7D%5D%20%2B%20%5B%5Cfrac%7B1000%7D%7B10000%7D%5D)
![Probability = [\frac{1}{10}] + [\frac{1}{10}]](https://tex.z-dn.net/?f=Probability%20%3D%20%5B%5Cfrac%7B1%7D%7B10%7D%5D%20%2B%20%5B%5Cfrac%7B1%7D%7B10%7D%5D)



or

Answer:
the farmer planned to have the work done in 6 days, and the area of the farm field is 120 times 6 = 720 hectares.
Answer:
B and F
Step-by-step explanation:
Given
x² + 4x + 4 = 12 ( subtract 4 from both sides )
x² + 4x = 8
Using the method of completing the square to solve for x
add ( half the coefficient of the x- term )² to both sides
x² + 2(2)x + 4 = 8 + 4, that is
(x + 2)² = 12 ( take the square root of both sides )
x + 2 = ±
( subtract 2 from both sides )
x = ±
- 2
= ± 2
- 2
Hence
x = 2
- 2 → B
x = - 2
- 2 → F