



 
Hi Sui, Let's simplify the numbers to see if your calculations seems reasonable. Suppose the sales for month of August 2000 were 5,000,000 IDR and the sales for month of October 2000: 10,000,000 IDR. The difference is 5,000,000 IDR and hence there is a 100% increase. Suppose the sales for month of August 2000 were 5,000,000 IDR and the sales for month of October 2000: 15,000,000 IDR. The difference is 10,000,000 IDR and 10,000,000 IDR is twice 5,000,000 IDR and hence there is a 200% increase. Suppose the sales for month of August 2000 were 5,000,000 IDR and the sales for month of October 2000: 25,000,000 IDR. The difference is 20,000,000 IDR and 20,000,000 IDR is four times 5,000,000 IDR and hence there is a 400% increase. Suppose the sales for month of August 2000 were 5,000,000 IDR and the sales for month of October 2000: 60,000,000 IDR. The difference is 55,000,000 IDR and 55,000,000 IDR is eleven times 5,000,000 IDR and hence there is a 1,100% increase. This is almost the same situation as your problem and the resulting percentage is almost the same. I checked your calculations and they look fine to me,  


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