Two racing boats set out from the same dock and speed away at the same constant speed of $101$ km$/$h for half an hour $(0\mathrm{.}500$ h$),$ the blue boat headed $25\mathrm{.}0$ south of west, and the green boat headed $37\mathrm{.}0$ south of west. During this half hour $($a$)$ how much farther west does the blue boat travel, compared to the green boat, and $($b$)$ how much farther south does the green boat travel, compared to the blue boat? Express your answers in km$.$