Question: Comparing Apples with Apples

Hi sir,

When there comes the percentile questions, I only come to know about the basics about percentile and not that much... So, I have found a bit difficulty when tackling percentile based question from 5lb manhattan book. My question is that- Is there any easier way to approach this sort of question?

300 test results are integers ranging from 15 to 75, inclusive. Dominick’s result is clearly in the 80th percentile of those results, not the 79th or the 81st.

Quantity A: Number of other test results in the same percentile as Dominick’s

Quantity B: Maximum number of other test-takers with the same result as Dominick

I am having problem in approaching percentile questions?
How can I gain more insight.