Elena can complete a website redesign task in 25 days, whereas Marcus can complete the identical task in 18 days. Marcus worked on the assignment for 12 days before leaving. How many days will it take Elena, working independently, to finish the remaining work?

The correct answer is $\frac{25}{3}$ days.

Step 1: Determine the individual work rates of Marcus and Elena.
Let the entire redesign task be represented as 1 whole unit of work.
Marcus can complete the task in 18 days, so the fraction of work completed by Marcus in 1 day is:
$\frac{1}{18}$
Elena can complete the task in 25 days, so the fraction of work completed by Elena in 1 day is:
$\frac{1}{25}$

Step 2: Calculate the work completed by Marcus before he left.
Marcus worked on the assignment for 12 days:
Work done by Marcus = 12 × $\frac{1}{18}$
Work done by Marcus = $\frac{12}{18}$
Simplifying the fraction by dividing both numerator and denominator by 6:
$\frac{2}{3}$

Step 3: Calculate the remaining fraction of work.
Remaining work = 1 - $\frac{2}{3}$
Remaining work = $\frac{1}{3}$

Step 4: Calculate the time taken by Elena to complete the remaining work.
Time taken by Elena = $\frac{\text{Remaining Work}}{\text{Elena's 1-Day Work Rate}}$
Time taken by Elena = $\frac{\frac{1}{3}}{\frac{1}{25}}$
Time taken by Elena = $\frac{1}{3}$ × 25
Time taken by Elena = $\frac{25}{3}$ days.

Therefore, it will take Elena $\frac{25}{3}$ days working independently to finish the remaining work.