International Data Systems' information on revenue and costs is relevant only up to a sales volume of 118,000 units. After 118,000 units, the market becomes saturated and the price per unit falls from $4.00 to $3.80. Also, there are cost overruns at a production volume of over 118,000 units, and variable cost per unit goes up from $2.00 to $2.20. Fixed costs remain the same at $68,000.

a. Compute operating income at 118,000 units.

b. Compute operating income at 218,000 units.