American Katie Ledecky has set a second world record in two days at the Pan Pacific championships. At Gold Coast, Australia, today, she shattered her own 1500-metre freestyle record.The 17-year-old school girl smashed her record by almost six seconds with a time of 15 minutes 28.36 seconds, to claim her fifth gold medal at the Gold Coast meet. It was only in June that Ledecky had set the previous record in the 1500 metres, a non-Olympic event, with a time of 15 minutes, 34.23 seconds. On Saturday, the teenager beat her 400 metres freestyle world record at the Gold Coast meet, eclipsing her previous mark by 0.49 seconds.Ledecky holds the world records in the 400 metres, 800 metres and 1500 metre freestyle, making her the first woman since US distance great Janet Evans to hold all three records at the same time. Ledecky has won the 200 metre, 400 metre, 800 metre and 1500 metre freestyle golds at the Pan Pacs and was also part of the American women's winning 4×200 metre freestyle relay team. Ledecky beat New Zealand's Lauren Boyle by more than 27 seconds in winning the 1500 metre gold.