I am working on ELISA and for my standard I used 50 ul of a 2222 ng/ml solution, I got the same signal as with 35 ul of a sample with unknown...

Hello I need help with this question.

I am working on ELISA and for my standard I used 50 ul of a 2222 ng/ml solution, I got the same signal as with 35 ul of a sample with unknown concentration. What is the concentration of that sample? how can I make this correction and know the concentration of the sample that should be higher than the standard because it is concentrated since the volume of the sample is lower