The Boardman family walked two over five of a mile in two over seven of an hour. What is their unit rate in miles per hour?

two-sevenths over two-fifths equals one and two-fifths miles per hour


two-sevenths over two-fifths equals five over seven miles per hour


two-fifths over two-sevenths equals one and two-fifths miles per hour


two-fifths over two-sevenths equals five over seven miles per hour