Chapter 1 - Measurement and Problem Solving - Learning Path Questions and Exercises - Exercises - Page 31: 67

$a). 1950,$ $b). 18750.$

The average number of hairs on human scalp = 125000. A healthy person loses about 65 hairs per day. a). In 1 month, a person will lose $65 \times 30 = 1950 \, hairs $ b). 15% of the hair is lost by 35 million men. So, the number of hairs lost $=\frac{15}{100} \times 125000=18750.$