100. To host a campus cultural and art festival, Class A and Class B are preparing to purchase a set of performance costumes for each student participating in the choir. If the two classes have a total of 92 people, and Class A has more people than Class B, with Class A having fewer than 90 people, the following is the price list provided by the supplier for the performance costumes:
\begin{tabular}{|c|c|c|c|}
\hline Number of costumes purchased & 1 to 45 sets & 46 to 90 sets & 91 sets and above \\
\hline Price per costume & 60 yuan & 50 yuan & 40 yuan \\
\hline
\end{tabular}

If the two classes purchase costumes separately for their respective students, they would have to pay a total of 5020 yuan.
(1) How much money can Class A and Class B save if they purchase the costumes together, compared to purchasing separately?
(2) How many students are there in Class A and Class B, respectively?
Reference answer: $1340,50,42$