Question

HELP!!! Monica measures the number of bacteria that are living on her petri dish. Each day, she measures the amount of change in the number of bacteria. These amounts create a geometric sequence. Use the data in the table to determine the sum of the amounts of change in the bacteria after the seventh day. Day Amount of Change in Bacteria 1 2 2 −8 3 32 4 −128 A) −6553.2 B) −10.8 C)6554 D)11.6

Answer 1

The correct option is;

C) 6554

Explanation:

The given data are;

Day, Amount of change in Bacteria

1, 2

2, -8

3, 32

4, -128

Given that the data follows a geometric sequence, we have;

The first term of the series = 2, the common ratio = -4, the sum of a geometric progression is given by the following formula;

`S_n = (a * \left (r^n - 1\right ))/(r - 1)`

Which gives;

`S_7 = (2 * \left ((-4)^7 - 1\right ))/((-4) - 1) = (2 * \left (-16384- 1\right ))/(-4 - 1) = (2 * \left (-16385\right ))/(-5) = 6554`

Therefore, the correct option is C) 6554.