Please check the question. The grammar is not clear. I'll assume the question is how many packs of $18 DVDs can be purchased with $126. 7 packs can be purchased (assuming no sales tax nor tip)
Step-by-step explanation:
"The store has CDs and DVDs <u><em>that you need how</em></u> many packs of DVDs came <u><em>by we won </em></u>and $126 if one pack costs 18 dollar"
I highlighted the confusing portions of the question.
I assume it swas meant to read as: "How many packs of DVDs can be purchased with $126 if they are $18/pack."
If you take the 2500$ he makes base salary and subtract from 4000$ you get 1500$ and if you multiply it by 1.80 you get the other needed 80% of the required sales.