Unless im being completely braindead right now there isn't a whole number that works with this. When simplified its 5/2 or 2.5 but because it isn't an actual whole number (like 2, 4 and 6) they don't count.
The answer to 250/100 would be 2.5 but that is a decimal and not a whole number. You couod round 2.5 to 3 to make it a whole nunber or you say that it is in between two whole nunbers which are 2 and 3 if you are allowed to. (since 2.5 alone is not a whole number)
1/3 of an hour is 20 minutes. If show 10 laps in 5 minutes, just divide 20 by 5, which gives you 4, then multiply 4 times 10. She can swim 40 laps in 1/3 of an hour. Hope that helps. Mark Brainliest if it does. Thank you!