A school year had 240 working days and a student attended 198 of them. The school requires at least 80 percent attendance. By how many days does this student's attendance exceed the minimum required?

The minimum is 80 percent of 240 = 192 days, and the student attended 198, so the surplus is 198 − 192 = 6 days. The figure 42 is the number of days missed, 240 − 198; 48 is the number he was ALLOWED to miss, 20 percent of 240, and since he missed only 42 of those the same 6-day surplus appears from that side too; and 24 is 10 percent of the year, a percentage the question never mentions.