Answer,:
increase in operating income by $840,000
Explanation:
The computation is shown below:
Offer price per unit $60
Less: Variable costs per unit: Â
 Direct materials ($20)
 Direct labor ($14)
 Variable overhead ($12)
 Variable selling $0
Incremental profit per unit (a) $14
Units offered to sell (b) 60,000
Effect on Operating Income (Increase) (a × b) $840,000
Therefore, in the case when the special order is accepted, the effect on operating income would be increase by $840,000