Where to put formula calculating total price?

Hello,
I have a event for with the price values: an adult pays 15 € an a child pays 10 €
When registering, one should indicate whether the member is a child or an adult (radio button).
Where to put the formula to calculte the total amount = 1_adult * 15 + 2_child * 10 + 3_child * 10 + 4_adult * 15 ?

I appreciate any helpful tip, I had to block registration until I have implemented a solution.

Sincerely,
Léon

A custom fee field should work for this.
With your existing radio button field, set your values as Child and Adult, check the fee field box, enter -5 and 0 as the fee values (if the event is 15€ priced) or 10 and 15 (if the event is 0€ priced), and set the field to display for Group Members.
See eventbookingdoc.joomservices.com/basic-s...ds/custom-fee-fields

Hello,
thank you very much, James.
Now that I have implemented the solution, I can explain my trouble in more detail.
1. I set up an event, and as I knew there were two different prices for adult and child, I put this info as text in the new explanatory filed (thank you Tuan for this feature).
2. When I published the event, the price text is only displayed when the event price is not zero, so I set a value of 10 into the price field. 3. This worked fine until the first user registered.
4. When the user registered, at the billing step a total price is calulated and displayed, which was #Registrants * 10, which of course is wrong if the members are composed of adults and childs.
5. In advance payment options, it is not possible to select "No payment method", but I remembered that Tuan once offered an additional payment plugin "os_osm_offline_cash.zip that would suit my needs, because the registrants should pay at arrival at this event.
But I didn't succeed getting this plugin to work correctly. Maybe I do not have the latest version, Tuan?
6. Finally, I implemented your suggested solution and set os_offline_payment, so I could reopen event registration.

Thank you again for your valuable support, to you both, James and Tuan.
Léon

I use latest Joomla ans EB 2.13.1

Hello Leon

I would need to check your settings to see what's wrong and guide you to correct it. So please submit a support ticket:

1. Sending us super admin account of the site

2. Send us the link to the event page

3. Tell me exactly how you want price to be calculated

I will check, correct the setup and make it works for you

Regards,

Tuan