Lucas is watering his lawn using the water stored in his rainwater tank. the water level in the tank drops 13 of an inch every 10 minutes he waters. what is the change in the tank's water level after 1 hour?

Some boys and girls were asked if they had a pet. one third of the group were boys. there were 20 boys. 20% of the girls had a pet. boys with a pet : girls with a pet = 1 : 5 i need to know how many girls there are.