Is this correct?

Marlon Audio Company manufactures video tapes. The desired speed of its model SF2000 is 4 inches per second. Any deviation from this value distorts pitch and tempo, resulting in poor sound quality. The company sets the quality specification to 40.17 inch per second because an average customer is likely to complain and return the tape if the speed is off by more than 0.17 inch per second. The cost per return is $28. The repair cost before the tape is shipped, however, is only $7 per tape. Compute L(x) if x is 4.12 inches per second. Estimate the tolerance for the firm to minimize its quality-related cost (loss). ound your answers to 4 decimal places.)