Using a geometric sequence, the number of emails sent on day 7 is given as follows:
A. 93,312.
A geometric sequence is a sequence in which the result of the division of consecutive terms is always the same, called common ratio q.
The nth term of a geometric sequence is given by:
[tex]a_n = a_1q^{n-1}[/tex]
In which [tex]a_1[/tex] is the first term.
This situation can be modeled by a geometric sequence with first term and common ratio given as follows:
[tex]a_1 = 128, q = 3[/tex]
Hence the number of people that receive the email on day n is:
[tex]a_n = 128(3)^{n-1}[/tex]
On day 7, the amount is:
[tex]a_7 = 128(3)^{7-1} = 93,312[/tex]
Hence option A is correct.
More can be learned about geometric sequences at https://brainly.com/question/11847927
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