Looking for tutoring help with calculating cpi and gst

[robynl]

Hi
Need tutoring or tips to help me calculate increasing an amount by 3.1% CPI and 10% GST over 3 years.
For the first year I have a starting amount of rent at 7300 which is required to be increased by 10% GST. I have calculated this to be 8030 - 7300*(1+0.10). No CPI is included in this first year.

For the second years rent using this amount of 8030 I need to add CPI of 3.1%. My thinking is 8030*(1+0.031) which equals 8278.93. Since GST was included in the amount of 8030 already I don't think I need to add GST for this year??

For the third year I have calculated the 8278.93 plus 3.1% - 8278.93* (1+0.031) =8535.58. Not sure if I need to add 10% GST to this amount.

Also need to calculate yearly rent total plus 10% GST - I have calculated that I should be multiplying monthly totals by 12. But I'm not sure how to multiply by 12 and then add the 10% GST.
Anyone that can give tips or tutoring - not looking for the answer as this is an assignment. I have been researching for ages but still stuck

 

[alansidman]

appears to be duplicate of https://www.mrexcel.com/forum/excel...sumer-price-index-gst-amount.html#post5088618

 

[Fluff]

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