So lets just assume first that there are a total of 2700 species of snakes all in all. Out of the 2700 snakes, 600 are known to be venomous. So first of all, let's get the number of the non venomous ones. Subtract 2700 and 600 and you will end up with 2100. So there are a total of 2100 non venomous snakes. So the fraction of the non venomous snakes will be 2100/2700. In its simplified form it is 7/9. In its decimal form (just divide it), you will get an answer of 0.7777.......
