Keep in mind that there are 100 centimeters in a meter.
The snail moves at a pace of 12 cm/h, and needs to go 100 cm. You can just divide 100/12 to get 8 1/3, which is how many hours (groups of 12 cm) it takes for the snail to travel 100 cm (1 meter).
If necessary, you can also multiply 8 1/3 by 60 to get the number of minutes the snail takes. 8 times 60 is 480, and 1/3 of an hour is 20, so add 480+20 to get 500 minutes.
