DGA Associates, Incorporated sells computer workstations designed for architects. In $2024,$ it sold $100$ workstations for $$374,000.$ For each workstation sold, DGA distributed a $30\%$ discount coupon for any additional future purchases made in the next $12$ months. Based on historical experience, DGA expects that approximately $25\%$ of the coupons will be utilized, and the goods purchased with the coupons would normally sell for $$420.$

Required:

$($a$)$ How many performance obligations are in a contract to purchase a computer workstation?

$($b$)$ Prepare a journal entry to record revenue for the sale of $100$ computer workstations, assuming that DGA uses the residual method to estimate the stand$-$alone selling price of the workstations sold without the discount coupon.