Settlement discount

Hi John. There's a qn that I am facing massive problems with. Please could you assist me: Lowe and Pricce Co. have annual credit sales of 12m$ and three months are allowed for payment. The company decides to offer a 2% discount for payments made within to two months. It is estimated that 50% of customers will take the discount. If the company requires a 20% return on investment, what will be the effect of the discount; assuming volume of sales remains unaffected. The answer is 247,123$ (net benefit of the discount) Please help me!