b$)$ Powders Sdn$.$ Bhd$.$ involves in processing and packaging crispy flour at Pekan Penaga. The operating costs incurred including packaging and delivery costs. The following are data on the operating cost and weights of crispy flour for the last $6$ months of $2023$:

Month Crispy flour $($kg$)$ Operating cost $($RM$)$

July $33,50063,460$

August $30,00064,200$

September $50,20079,200$

October $55,00080,450$

November $43,20073,440$

December $48,50081,700$

Based on the above information, you are required to use the High$-$Low method to determine the followings:

i$)$ variable cost per unit;

ii$)$ fixed cost;

iii$)$ cost function; and operating cost incurred if the weight of crispy flour is $163,000$ kg$.$