The data given in the problem is the weight of the two boxes that is 9.4 lb and 62.6 lbs. The problem wants to find out the total rounded off weight of the two boxes. Rounding off numbers is the process by which you make the numbers easy to use but keep them closer to its original value. It maybe not that accurate but it is surely easier to use compared to the original ones with complex decimal points. The sum of the two given weights in the problem is 72. To round off the number 72 that becomes 70 because 72 is closer to 70 however from 76 up will be rounded up to 80.
