Imagine that the amount of bacteria in a petri dish grows exponentially through time, doubling every day until the dish is completely covered by bacteria on day 100. On what day would the petri dish be 50% covered by bacteria?

Correct  50% will be on day  99

Step-by-step explanation:

Given:

- amount of bacteria is doubling every day

- on day 100 amount is 100%

- on day n = ? will be 50%

We define the initial amount of bacteria with A

First day  -  A₁ = A · 2

Second day - A₂ = (A · 2) · 2 = A · 2²

Third day - A₃ = A₂ · 2 = A · 2³

n-th day   Aₙ = A · 2ⁿ

on day 100   A₁₀₀ = A · 2¹⁰⁰   -  100%

on day  n     Aₙ = A · 2ⁿ         -    50%

A₁₀₀ : Aₙ = A · 2¹⁰⁰ : A · 2ⁿ =  100% : 50% = 2 : 1

(A · 2¹⁰⁰) :  (A · 2ⁿ)  = 2 : 1   ⇒ A · 2ⁿ  = (A · 2¹⁰⁰) / 2 ⇒

2ⁿ  = 2¹⁰⁰ / 2¹ = 2⁹⁹ ⇒ 2ⁿ  = 2⁹⁹ ⇒ n = 99

n = 99

This problem could have been solved more simply. If we know that the quantity increases double every day, it is logical if 99 days is 50% that on the 100th day it will be double or 100%

God is with you!!!

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step-by-step explanation:

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the correct answer is a) they believe they have a "just cause."

islamic terrorists justify their violent actions because they believe they have a "just cause."

every act of terrorism of islamic sects is done “in the name of allah”. that justifies their actions. islam people who commit those terrorist attacks are not afraid to die. that is why the attacks have horrible consequences. they know they are going to die and they are proud to do it because it is in the name of allah, so it is justified and is for a “good cause.”

since the very beginning of the conflict with israel, islam is fighting a “sacred war”, respecting the words stated in the qur’an. they fight against the domination of the western countries and to defend their occupied territories.