A New Way of Grading Practice?

I love how Khan Academy is free, (with no subscriptions mind you), and how accessible it is, but I find having to restart all over again in a practice to receive full marks to be infuriating.

Could there be some sort of system, that if you get a question wrong in practice, that then you could get another one to solve, (of similar theme), so that you'll need to altogether complete 3-4 questions right?

Example:

Q.1 Correct +1 pt.       1/4
Q.2 Correct +1 pt.       2/4
Q.3 Incorrect 0 pt.       2/4
 and so on... until they get 4 pts. total.

Thank you for your time.