Since you're only asking how to solve, I won't give you the answers, just what you need to solve the problems.
Problem 7 is asking who brought their lunch the greatest percent of the time. To find this, divide the days they brought their lunch by the number of days (for example, Marci's would be 6/15, or 40%)
Then just compare the amounts and you'll get the answer.
Problem 8 is basically the same, but much less steps. Just figure out the percent in each answer. (for example, A is incorrect because 4/23 gives you about 17%)