Afamily has seven sons. the chance that their eighth child will be a daughter is

one chance in seven
one chance in eight
one chance in two
practically none

Every weekday, mr. jones bikes from his home to his job. sometimes he rides along two roads, the long route that is shown by the solid lines. other times, he takes the shortcut shown by the dashed line. how many fewer kilometers does mr. jones bike when he takes the shortcut instead of the long route?