The depth of a river 500 ft. wide was measured at six equidistant places in a line directly across from it, and found to be 2 ft., 3 ft., 4 ft., 4 1/2 ft., 2 ft., 1 1/2 ft., and being very shallow at the margins, the dept was called 0. Five measurements of the current along the same line showed it to be 1/5 mi., 1/2 mi., 1 mi., 1/4 mi., and 1/10 mi. per hour. How many barrels of water would the river discharge in 24 hours?
Source: E. Olney’s The Science of Arithmetic, 1876