Timed Quant Practice - Hard Section 2 Sample #2; Questino 12

Is there a way to do this with a formula instead of the table method as shown in the video found here: Solutions

Possible Answer choices are 5, 8, 10, 12, and 15.

Not sure where the solution is so uhhh missing context

Sorry, can’t link the exact video but it is in the timed quant practice hard section 2 video. I think like three quarters through the video.