The daily wages of 100 workers are grouped as — ₹200–300: 12 workers, ₹300–400: 25 workers, ₹400–500: 38 workers, ₹500–600: 15 workers, ₹600–700: 10 workers. What percentage of the workers earn ₹400 or more a day?

Add the three classes from ₹400 upwards: 38 + 15 + 10 = 63 workers out of 100, that is 63 percent. The complement, 12 + 25 = 37 percent, earn under ₹400. Taking only the class that begins at ₹400 gives 38 percent, and stopping at ₹600 gives 38 + 15 = 53 percent, quietly dropping the top class. The total frequency is 100 here, so the count and the percentage happen to be the same number — a coincidence worth noticing but not relying on.