An assessee depreciated the machinery of his factory by 10% each in the first two years and by 40% in the third year and thereby claimed 21% average depreciation relief from taxation department, but...

An assessee depreciated the machinery of his factory by 10% each in the first two years and by 40% in the third year and thereby claimed 21% average depreciation relief from taxation department, but the I.T.O. objected and allowed only 20% Show which of the two is right.