This is because double bonds are two pairs of electrons are shared between atoms and triple bonds are three pairs, and one pair of electrons is 2, so 2 x 2=4 and 2 x 3=6.
because it 12:00 and the storm is moving at 25km/hr and it 75 km away that means in three hours the storm would hit your town so at 3:00 the storm would hit at your at ends at 2:00 so yes you would get home before he storm hit.