Tammy can eat twice as many pickle slices as Sammy who eats 15 so Tammy can eat 15*2 = <<15*2=30>>30 pickle slices
Ron eats 20% fewer pickle slices than Tammy who eats 30 pickle slices so that's .20*30 = <<20*.01*30=6>>6 fewer slices than Tammy
Tammy eats 30 slices and Ron eats 6 less, then Ron eats 30-6 = <<30-6=24>>24 pickle slices
#### 24