julia studied math for 3 1/3 hours during the 4 days before her lastmath test. What was the average amount of time she studied e
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Answer:
Step-by-step explanation:
Given the series 8 + 18 + 28 + 38
First, we need to find the sum of the nth term of the sequence as shown
Sn = n/2[2a+(n-1)d]
n is the number of terms
a is the first term = 8
d is the common difference = 18-8 = 28-18 = 10
Substitute
Sn = n/2 [2(8)+(n-1)*10]
Sn = n/2 [16+10n-10]
Sn = n/2[10n+6]
Sn = 2n/2(5n+3)
Sn = n(5n+3)
Sn = 5n²+3n
In Sigma form;