Solution:

Adjustment for the cost of the different size or capacity of the cyclone dust collector need to be purchased can not be calculated directly. Note that while the new units has 10 times the capacity as the unit purchased in 1985 will cost 10X more, because of economy of scale. However, the purchase cost will have increased because of inflation in the 27 years since it was purchased in 1985. Assuming cost inflation or 5 % per year, the original cost of $35,000 is now equivalent to

new cost for the 100 ft^3/min = [$35,000 x 5%] + $35,000 = $36,750
if 100 ft^3/min = X
1000 ft^3/min = 10X

Thus, the estimate of the cost to purchase 1000 ft^3/min in 2012 = 10X = $367,500