You have already posted this question here:https://www.physicsforums.com/showthread.php?t=363405 [Broken]
If you made some progress on it, you should add a reply to the original question, rather than create a new thread.
I think a drawing would be in order for this problem, as you say one child is jumping and the other is sliding. How are the two children (who are extremely heavy at 65 and 85 kg for children) positioned in relation to each other?
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