To solve this question, you need to know how to set up a system of equations using the given information and how to solve for the unknown variable. Here is one possible explanation:

Let $x$ be the number of bottles that Jim fills in one minute and $y$ be the number of bottles that Molly fills in one minute. Then, we have the following equations:

• $x + y = 30$ (the total number of bottles filled by Jim and Molly in one minute $\frac{900}{30}$)

Statement 1 tells us that $y = x/2$, which means that Molly fills half as many bottles as Jim in one minute. We can substitute this into the first equation and get:

• $x + x/2 = 30$
• $3x/2 = 30$
• $x = 20$

This means that Jim fills 20 bottles in one minute and Molly fills 10 bottles in one minute. We can use this to find how long it takes Molly to fill the bottles by herself:

• $30y = 900$
• $30(10) = 900$
• $y = 30$

So, Molly takes 30 minutes by herself to fill the bottles. Therefore, statement 1 alone is sufficient to answer the question.

Statement 2 tells us that $45x = 900$, which means that Jim would take 45 minutes by himself to fill the bottles. We can solve for x and get:

• $x = 20$

This is the same as what we found from statement 1, so we can use it to find how long it takes Molly to fill the bottles by herself:

• $y = x/2$
• $y = 20/2$
• $y = 10$

So, Molly fills 10 bottles in one minute and takes 30 minutes by herself to fill the bottles. Therefore, statement 2 alone is also sufficient to answer the question.

Since both statements alone are sufficient, the correct answer is D. Each statement alone is sufficient.