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:
Mrs. Delgado purchased 6 notebooks and 2 packages of pens.
Step-by-step explanation:
Given that Mrs. Delgado purchased notebooks at 2 for $ 5 and pens at $ 2 per package, and she spent $ 19 for a total of 8 items, to determine how many notebooks and pens did she buy the following calculation must be performed:
5/2 = 2.5
8 x 2.5 + 0 x 2 = 20
6 x 2.5 + 2 x 2 = 19
Therefore, Mrs. Delgado purchased 6 notebooks and 2 packages of pens.
Write an equation system based on the problem. For an instance, x represents the number of $3 tickets sold and y represents the number of $5 tickets sold.
x + y = 40
3x + 5y = 136
Solve the equation system using elimination method. Use elimination of y in order to find the value of x
x + y = 40 (multiplied by 5)
3x + 5y = 136 (multiplied by 1)
-----------------------------------------
5x + 5y = 200
3x + 5y = 136
------------------ -
2x = 64
x = 64/2
x = 32
The value of x is 32. She sold 32 tickets worth $3
Answer:
the answer is 108 ft²
Step-by-step explanation:
multiple 18 to 6