9. Sheila works 8 hours per day on Monday, Wednesday and Friday, and 6 hours per day on Tuesday and Thursday. She does not work on Saturday and Sunday. She earns Tshs 32,400 in those working days per week. How much does she earn per hour?
22. In a group of 40 people, 10 are healthy and every person of the remaining 30 has either high blood pressure, high level of sugar content in the body or both. If 15 people have high blood pressure and 25 people have high level of sugar content in their bodies, how many people have high blood pressure and high level of sugar content?
23. From the top of a 200 metres high building, the angle of depression to the bottom of a second building is 20°. From the same point, the angle of elevation to the top of the second building is 10°. Calculate the heigh of the second building correct to 2 decimal places.