Final answer:
The price received by suppliers (PS) after a $3 per unit tax is imposed on producers in a market is $69 per unit.
Step-by-step explanation:
To find the price received by suppliers (PS) after a $3 per unit tax is imposed on producers in a market, we need to subtract the tax amount from the price paid by consumers (PB). In this case, PB is given as $72. So, PS = PB - Tax. PS = $72 - $3 = $69 per unit.