Answer: increase her consumption of carry-out lunches and decrease her consumption of magazines.
Explanation:
Melika should buy more of the good that gives her more utility per dollar spent.
Magazine utitlity per dollar spent:
= Marginal utility / Price
= 10 / 5
= 5 per dollar
Carry-out lunches:
= 21 / 3
= 7 per dollar
Carry-out lunches give her a greater utility per dollar so Melika should consume more of that than magazines.