A young researcher wants to test how well extremophiles, organisms that thrive in extreme conditions, live in different environments. She will do this by putting extremophiles of different species into different solvents. Because of limited lab space, she can run only one sample at a time, and each sample must remain undisturbed for 7 days. To reduce the total time needed to process all samples, the researcher decides to use two acidic solutions along with a control. The information below includes the extremophiles and the solvents the researcher will use in her tests.

\begin{tabular}{|c|}
\hline \begin{tabular}{l}
Species of \\
Extremophiles
\end{tabular} \\
\hline T. prosperus \\
\hline A. aceti \\
\hline A. brierleyi \\
\hline H. acidophilum \\
\hline
\end{tabular}

\begin{tabular}{|l|c|}
\hline \multicolumn{1}{|c|}{ Name } & [tex]$pH$[/tex] \\
\hline hydrochloric acid & 1.3 \\
\hline ascorbic acid & 4.2 \\
\hline water & 7.0 \\
\hline
\end{tabular}

Based on the tables, how many days will all of the researcher's experiments take? You may use the calculator.

A. 7
B. 21
C. 49
D. 84



Answer :

To determine how many days all of the researcher's experiments will take, let's break down the problem step-by-step:

1. Identify the number of extremophile species and solvents:
- There are 4 species of extremophiles:
- T. prosperus
- A. aceti
- A. brierleyi
- H. acidophilum

- There are 3 different solvents:
- hydrochloric acid
- ascorbic acid
- water

2. Calculate the total number of experiments:
- Each species of extremophile will be tested in each solvent.
- Number of species [tex]\( \times \)[/tex] Number of solvents = Total number of experiments
- [tex]\( 4 \text{ species} \times 3 \text{ solvents} = 12 \text{ experiments} \)[/tex]

3. Determine the number of days each experiment will take:
- The researcher allows each sample to remain undisturbed for 7 days.

4. Calculate the total number of days for all experiments:
- Total number of experiments [tex]\( \times \)[/tex] Number of days per sample = Total number of days
- [tex]\( 12 \text{ experiments} \times 7 \text{ days per experiment} = 84 \text{ days} \)[/tex]

Thus, the researcher's experiments will take a total of 84 days.

The correct answer is:

D. 84