Relevant cost:

Relevant cost relates to the cost, which is linked with a specific decision of the administration and may vary in the future due to the judgement taken. It helps to remove the irrelevant information from the process of decision making.

Scaling up cost;

Cost if 4,500 Gallons per hour centrifuge = (4,500 / 1,500) ^ {0.75} \$40,000

=> 91,180

Thus, the approximate cost now = 91,180 (500 / 125)

=> 91,180 * 4

=> 3,64,720