The ratio of males to females at jones high school is 5: 4. if there are 800 females that attend jones, how many males attend?

To answer this you will use the given simple ratio of 5 males for every 4 females to answer the question.

If there are 800 females this means there are 200 groups of the 4 females from the original ratio. This also means there are 200 groups of the 5 males resulting in 1000 males.

There are 1000 males at Jones High School.

The answer to your question is b