Josh is a 16 year old lifeguard at Sunset Golf Course. He gives swimming lessons to children while their parents are golfing. Josh is to make sure that no one dives into the pool from the side. Josh failed to warn a new girl named Juanita about this danger. Juanita sustained serious injury when she hit her head on the concrete on the bottom of the pool. Who is liable for Juanita's injury? Explain your answer in details.