The travelling time from Double Tree hotel to CPF Maxwell  is as follows:
1. hotel to JB checkpoint
mean: 10 mins, std deviation 5 mins

2. JB checkpoint to Woodland checkpoint
mean: 50 min, std deviation 10 mins

3. Woodland checkpoint to CPF MAxwell
mean: 40 min, std deviation 10 mins

Calculate total time needed to reach CPF Maxwell from Double Tree hotel with 80% probability.