Final answer:
To find the percentage of Snickers in the candy bag, divide the number of Snickers by the total number of candies and multiply by 100. In this case, the percentage is 40%.
Step-by-step explanation:
To find the percentage of Snickers in the candy bag, we need to divide the number of Snickers by the total number of candies and then multiply by 100. In this case, there are 12 Snickers out of 30 candies in total. So, the percentage of Snickers is (12/30) * 100 = 40%. Therefore, the correct answer is a) 40%.