For the purposes of ascer 864 taining the assessable value, if three of the components namely, the cum duty selling price, the quantum of permissi ble deductions and the rate of excise duty are known, the proper and appropriate method of determining the assessable value would be the following formula: Assessable value = cum duty selling price permissible deductions divided by ( 1 + Rate of excise duty) Thus in the instant case working backward, if the cum duty selling price is known to be Rs.3200 and the permissi ble deductions are known to be Rs.200 and the rate of excise duty is known to be 60% the assessable value is computed aS under: Selling price permissible deductions = Rs.3200=RS.200 = Rs.3000 Assessable value is equal to difference in selling price and permissible deductions divided by 1 plus 60/100 which is equal to 3000/1.6 which is equal to Rs. 1875.