The first class in a relative frequency table is 50-59 and the corresponding relative frequency is 0.2What does the 0.2 value indicate?

The sum of the relative frequencies must equal 1 (or 100%), because each individual relative frequency is a fraction of the total frequency. The relative frequency of any category is the proportion or percentage of the data values that fall in that category.

Relative frequency = relative in category/ total frequency

It means a number in that class appeared 20% of the total appearances of all classes