 
<translate> Ga kowane nau'in rigar, yana buƙatar saya, ma'aikata 40 / 4 = riguna 10. T-shirts na fararen fararen fararen farashi $ 20 / shirt * 10 shirts = $ 200. Fararen T - shirts na mata sun rage dala 5, ko ($ 20 / shirt - $ 5 / shirt) * 10 shirts = $ 15 / shirt * 10 shirts = $ 150. T-shirts na baƙar fata na farashi, $ 18 / shirt * 10 shirts = $ 180. T-shirts na mata baƙar fata sun rage $ 5 ƙasa, don haka ($ 18 / shirt - $ 5 / shirt) * 10 shirts = $ 13 / shirt * 10 shirts = $ 130. Yanzu ka ƙara dukan waɗannan adadi don ka samu jimillar: $200 + $150 + $180 + $130 = $660. Amsar ƙarshe: 660. <eng> For each type of shirt, he needed to buy, 40 employees / 4 = 10 shirts. White men's T - shirts cost $20 / shirt * 10 shirts = $200. White women's T - shirts cost $5 less, or ($20 / shirt - $5 / shirt) * 10 shirts = $15 / shirt * 10 shirts = $150. Black men's t - shirts cost, $18 / shirt * 10 shirts = $180. Black women's T - shirts cost $ 5 less, so ($18 / shirt - $5 / shirt) * 10 shirts = $13 / shirt * 10 shirts = $130. Now add up all these quantities to find the total: $200 + $150 + $180 + $130 = $660. The final answer: 660. 