We have a cumulative frequency that ends in 100. So we can conclude that the total sample is of a size of 100 batters.
The number of people that had 75 or more RBIs can be calculated substracting from the 100 people the cumulative frequency for 75 RBIs (that represents the number of persons with RBI of 75 or less), that has a value of approximately 72.
Then, (100-72)=28.