Its a simple analytical question to see if you can perform simple optimization under constraints. It exercises your analytical skills without requiring any particular mathematical background.
Any high level engineering job will involve some proficiency with computing expectations and solving constrained problems, for scaling or building supply chains. Programming is not necessarily a skills based trade like carpentry, some high level thinking always helps.
Straight up engineering IC position (webkit many many many many years ago, long before chrome existed, before safari for windows, before ye olde iphone)