Explanation:
If 15 sundaes are mint ice cream, then there are 30 - 15 = 15 sundaes remaining.
Out of these 15 sundaes, 12 are chocolate, leaving 15 - 12 = 3 sundaes to be vanilla.
Since 1 unit equals 6 sundaes, there is 1/6 of a unit of vanilla sundaes, which is less than half of a unit. Therefore, Ivania will make 0 units of vanilla sundaes.
To find the total number of chocolate and vanilla sundaes, we add the number of chocolate sundaes (12) to the number of vanilla sundaes (0). Therefore, the total number of chocolate and vanilla sundaes is 12.