Answer:
52
Step-by-step explanation:
sorry if it's wrong
Yes 28/30 is bigger than 4/5.
For

and

to be inversely proportional, there must be some constant

such that

Given that

when

, it follows that

Then when

, we have
Red shirts and blue shirts equally count to his bonus, so he has 15 + 23 = 38 shirts sold at this moment. He needs to sell 75 shirts for the bonus. We subtract our goal from what he have; 75 - 38 = 37.
The strategy here: subtract the goal (75 shirts) from what you did to get to the goal (15 shirts and 23 shirts).
Nathan needs to sell 37 more shirts for the bonus. Hope this helps.