Anna has been studying a type of bacteria that triples every month. originally, there were 4 bacterial cells. she wants to know how many there will be after 15 months. which equation should she use? . a15 = 4(3)(15). a15 = 4(3)15. a15 = 4(3)15 − 1. a15 = 4(3)(15 − 1). @perl . @darkbluechocobo

Explanation:

Given,

Original number of bacterial cell = 4,

Also, the number of bacterial cell triples every month,

So, the number of bacteria after one month = 3 × 4 = 4(3)

After two months = 3 × 4(3) = 4(3)²,

After three months = 3 × 4(3)² = 4(3)³,

......................................................... , so on,

Thus, the number of bacterial cell after 15 months,

For 15 months, x = 15,

Hence, the number of bacterial cells after 15 months,

Which is the required equation she should use.

Option A

Explanation:

The initial number of bacteria's is equal to

This number get tripled every month which means after one month  the number of bacteria's will be

After two months the number of bacteria's will be

After three months the number of bacteria's will be

i,e after three months total number of bacteria's is equal to

Thus, after three months total number of bacteria's is equal to

Hence, option A is correct

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