The answer to the seventh question on page 64 of the second volume of mathematics in the fifth grade, please, 3Q.
One eighth means that a person's height is divided into eight parts on average, of which the head accounts for 1 part. Three fifths means that the water level in the main stream of the Yangtze River is divided into five parts, and three tenths of the polluted water is 10, of which three parts are salt water.