Find the percent of change. original: 80, new: 64

How do you do this geometry problem

The following frequency table relates the weekly sales of bicycles at a given store over a 42-week period.value01234567frequency367108521(a) in how many weeks were at least 2 bikes sold? (b) in how many weeks were at least 5 bikes sold? (c) in how many weeks were an even number of bikes sold?

15m is what percent of 60m; 3m; 30m; 1.5 km? the last one is km not m