Chapter 7 – Example 6

Hi Sir, thanks for a great lecture.
Please could you explain the below;

MR=MC = 120 – (2 x 0.001 Q) = 5
115 = ( 2 x 0.001) Q

I’ve understood the whole method, however I don’t quite understand how you arrived at 115, I thought it would be 100 as that’s the SP per unit.

Apologies if the its a very straightforward answer.

Thanks,
Tas