Can you give me some step-by-step instructions for this math problem: There are 30 students in Marissa’s class. Each student started the year with 10 pencils. After two months, 1/5 of the total pencils in class were used. At the end of the year, only 1/3 of the remaining pencils were left. How many pencils were left?
There were 30 x 10 = 300 pencils in the class at the start of the year.
After two months, 300 x 1/5 = 60 pencils were used.
Thus, 300 - 60 = 240 pencils were left unused after two months.
Therefore, 240 x 1/3 = 80 pencils were left at the end of the year.