Nishimoto Store's analysts completed their report for the Controller. Nishimoto manufactures and sells two products with selling prices and variable costs as follows:

A B

Selling price $18.00 $22.00

Variable costs 12.00 14.00

Nishimoto's total annual fixed costs are $38,400. Nishimoto sells four units of A for every unit of B. If operating income last year was $28,800, what was the number of units Nishimoto sold?