In a class of 500 students, the grades were given as percentile. Fred's grade was 20th percentile, George's grade was 40th percentile and Harry's grade was 60th percentile.
\(\begin{array}{ll}
\text { Ouantity } \boldsymbol{A} & \text { Ouantity } \boldsymbol{B} \\
\text { Number of grades } & \text { Number of grades } \\
\text { between Fred's grade } & \text { between George's grade } \\
\text { and George's grade. } & \text { and Harry's grade }
\end{array}\)
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