Answer:
40 minutes
Step-by-step explanation:
The ratio of the number of words to the number of minutes is constant. Then, If violet read 1250 words in 5 minutes, we can write the following equation:

Where x is the number of minutes that she needs to read a 10000-word essay.
So, solving for x, we get:

Then, she will take 40 minutes to read the essay.