1 hour is 60 minutes, and there are four 15 minute intervals. So, if there are four intervals of 15 minutes that add up to 60, just take three of them and put them over four: 15.15.15.1515.15.15β=6045β Or we could multiply one hour or 60 minutes by 43β =60Γ43β=160β.43β=4.160.3β=4180β=45