Bobby has a party while his parents are away for the weekend. Bobby estimated that if his 9 friends hep him to clean the house,

Question

2 years ago

10

Bobby has a party while his parents are away for the weekend. Bobby estimated that if his 9 friends hep him to clean the house,

they will finish in time if they start 8 hours before his parents return. But after only two hours of cleaning, Bobby's parents call and say they are just two hours from home. How many more friends does Bobby need to call to help finish cleaning in time.

Mathematics