3. Marie-Pascale solves 4 math problems per day. Kaeli solves $x$ math problems per day. Over a number of days, Marie-Pascale solves a total of 72 problems. Over the same number of days, Kaeli solves 54 more problems than Marie-Pascale. What is the value of $x$ ?
3. Since Marie-Pascale solves 4 math problems per day and solves 72 problems in total, this takes her $72 \div 4=18$ days.
Since Kaeli solves 54 more problems than Marie-Pascale, she solves $72+54=126$ problems.
Since Kaeli solves $x$ problems per day over 18 days and solves 126 problems in total, then $x=\frac{126}{18}=7$.
ANSWER: 7