First note that the marginal cost for the museum to allow one more child (or a family) is $0. That is irrelevant to pricing regardless of what some guru says about future of pricing.
This is a case of metered price discrimination combined with partitioned pricing. Do not look at this as two separate price points for parent and children. This is just one total price. The museums want to charge a fixed price per family. If you assume a simple case of one parent per child combination, the museums want them to pay one total price for their entry.
Some parents may find the total price too high and may not use the museum but others will.
Once they decided the total price for parent-child pair it becomes a question of how to partition it between parent and child.
- They could simply not partition, setting one price for the pair. That would result in the customer (the parent) assigning all the price to just one and see value mismatch. Research on combined vs. partitioned pricing suggest the single price will not be received well with the customers.
- Charge all the price to parent or child and call the other one as free. This has the same effect as previous case.
- They could share the total price evenly and set same price for both adult and child. But that goes against the reference price in the minds of the customers on priced they pay for children. Same reason they cannot assign higher share to the child.
Hence we have the case we see everywhere despite value delivered to the customer, parents tickets are priced higher than the that of children’s.
A case of partitioned pricing.