Test to 100% with remediation

I'm new to the Storyline community and need help. I need to create an exam with following requirements:

If  score is less than 90, I need to show the learner the answers and remediate them on the questions they missed. Then I must give only the missed questions to them again and let them try to answer them correctly until the overall score would be 90 or higher. Ultimately,  I need to store all the learner's responses via interaction data and submit the total score to the lms.

My problem today is that I am not retaining the score or answers from the first attempt.  When I remediate the learner on their missed questions and give them a second attempt at those missed questions,  the score only reflects the total percentage of the missed questions.  For example,  if I score 70% on a 10 question exam,  and then retake the 3 questions I missed. If i get 2 of those 3 questions correct my score should be 90% and completion criteria would be met.  However,  in this example,  the only information getting submitted to the lms is 20% (because i answered 2 of the 3 correct). I need this to concatenate the score and send all learner responses to the lms.

Hopefully someone can help me out! 

Thanks. 

Using Storyline 360

I can't seem to