Answer:
Bacteria, algae and other organisms thrive under warm water conditions this is obviously harmful not just for athletes but the general public in a commercial swimming pool, for competitive pools the water should be no higher than 82°F (28°C), for recreational pools the recommended maximum is 84°F (29°C).
Step-by-step explanation:
There are, 20475 different groups are possible if the manager wants to select one group of 4 people from his 28 assistants.
<h3>What is permutation and combination?</h3>
A permutation is the number of different ways a set can be organized; order matters in permutations, but not in combinations.
We have:
A manager wants to select one group of 4 people from his 28 assistants.
The total number of groups possible = C(28, 4)

After calculating:
= 20475
Thus, there are, 20475 different groups are possible if the manager wants to select one group of 4 people from his 28 assistants.
Learn more about permutation and combination here:
brainly.com/question/2295036
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W- (3,4)
Z- (-1,1)
X-(-1,-3)
Y-(-4,1)
A pharmacist has 40% and 80% of iodine solutions on hand. How many liters of each iodine solution will be required to produce 4 liters of a 50% iodine mixture?
.
Let x = liters of 40% iodine
then
4-x = liters of 80% iodine
Using algebra:
.40x + .80(4-x) = .50(4)
.40x + 3.20-.80x = 2
3.20-.40x = 2
x = 4 liters (40% iodine)
80% iodine:
4-x = 4-4 = 0 liters needed (80% iodine)