The first term will be 3 and the sum of the first 9 terms will be 81.
<h3>What is Arithmetic progression?</h3>
The difference between every two successive terms in a sequence is the same this is known as an arithmetic progression (AP).
The arithmetic progression has wider use in mathematics for example sum of natural numbers.
Natural number = 1,2,3,4,5,6,7,8...
Given,
Six terms as 10.5
So,
a₆ = 10.5
Common difference(d) = 1.5
The nth term of an AP is given by
= a + (n-1)d
So,
a₆ = a + (6-1)d
10.5 = a + 5(1.5)
a = 3
Now,
The Sum of n terms is given by
S = n/2[2a + (n-1)d]
S = 9/2[6 + 8(1.5)]
S = 81
Hence the first term will be 3 and the sum of 9 terms will be 81.
For more about Arithmetic progression
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The amount of drugs that will be left after 12 hours is 17.42 mg provided Sarah takes 550 mg of an antibiotic every hour.
<h3>What is exponential decay?</h3>
Exponential decay can be described as a reduced amount of an original substance by a definite percentage over a period of time. It can be determined by using the formula:

where;
- y = total amount,
- a = initial amount = 550 mg
- r = the growth rate = 0.25
- t = number of growth periods = 12 hours

y = 17.42 mg
Therefore, we can conclude that the amount of drugs that will be left after 12 hours is 17.42 mg.
Learn more about the exponential decay model here:
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Answer: the total length of the string is 9 meters.
Step-by-step explanation:
The total number of strings that Emily measured is 3.
The length of the first piece of string measures 642 cm.
The length of the second piece of string measures 124 cm.
The length of the third piece of string measures 134 cm.
Therefore, the total length of the 3 pieces of string would be
642 + 124 + 134 = 900 cm.
100 cm = 1 m,
Converting 900 centimeters to meters, it becomes
900/1100 = 9 meters
34.60 or 35
Depends on what to round, tenths or hundreds....
Answer:
0.25g+7.75 less or equal to 8.25
Step-by-step explanation: