If a shark can swim 4 kilometers in 1/10 of an hour and a blue whale can swim 5 kilometers in 1/4 of an hour then we can multiply 5 kilometers by 4 and 4 kilometers by 5 then we get both of them have travled 20 kilometers. Then we multiply 1/10 by 5 and 1/4 by 4 and we get that the shark travled 20 kilometers in 5/10 of an hour (or half an hour) and the blue whale travled 20 kilometers in 1 1/4 of an hour (or 1 hour and 15 minutes)
