The girl's speed is 1380mm/sec * 1cm/10mm * 60sec/minute (since 1cm=10mm and 60 sec=1 minute)= 1380*60cm/10min= 1380*6cm/min =8280 cm/min. For the turtle, we have 1584 m/hr * 1 hr / 60 min * 100 cm /1m (we have to make sure that they cross out, so e.g. for the hour we multiply it by 1 hr/60 min since the original hour is on the bottom)= 158,400cm/60min =15840cm/6min = 2640 cm/min Since the girl is 8280 cm/min and the turtle is 2640 cm/min, we divide them to get 8280/2640= around 3.136 cm/min
The probability is the number of chances divided by the total number of cards. The total number of cards is 8 + 6 +1 = 15. There are 8 red cards and therefore 8 chances to get red.
8 out of 15 cards is 8/15. The probability is 8/15.
