Two high-speed ferries leave at the same time from a city to go to the same island. The first ferry, the Cat, travels at 28 miles per hour. The second ferry, the Bird, travels at 21 miles per hour. In how many hours will the two ferries be 7 miles apart?

You didn’t put the necessary image to solve the question : p

The question is kind of confusing. if it's asking how many variations of answers can you give. then do 4^5 for your answer.this would be something like the first question could be a and the 2nd c or first b next c etc. if you can, ask the teacher for a better confirmation of what it's asking. if i'm assuming correctly what it's asking, it's 625 different variations.