Answer:
S₁₅ = 645
Step-by-step explanation:
The sum to n terms of an arithmetic sequence is
= 
[ 2a₁ + (n - 1)d ]
where a₁ is the first term and d the common difference
Using the nth term formula 
= 5n + 3 , then
a₁ = 5(1) + 3 = 5 + 3 = 8
a₂ = 5(2) + 3 = 10 + 3 = 13 , then
d = a₂ - a₁ = 13 - 8 = 5
Thus
S₁₅ = 
[ (2 × 8) + (14 × 5) ]
= 7.5( 16 + 70)
= 7.5 × 86
= 645
The image is blurry
Step-by-step explanation:
The percentage of tardiness among the 102 pupils is 2.94.
<h2>Calculation of the percentage</h2>
According to the query,
Course A: Total number of students = 102
Number of tardy students = 3
Percent of students tardy in course A = (number of tardy students/total
number of students) * 100
=(3/102)*100
= 2.941
≈2.94
In case of course B: Total number of students = 85 & tardy student = 5
So, the percent of tardy student = (5/85)*100 = 5.88 %
Therefore, it is concluded that the percentage of student tardiness in course A is 2.94.
Learn more about the percentage here:
brainly.com/question/92258
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Answer:
44.6
Step-by-step explanation:
Since the sides with the two tick marks are equal to 7.4, and there are three of these sides, they are equal to 7.4 times 3, which is 22.2. The remaining sides have 1 tick, meaning they are 11.2, meaning this is 11.2 * 2, which is 22.4. The combined perimeter is 44.6 cm.
