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CP2 September 2019 Paper 2 Q3 Scenario 4 - Goal Seek

M

Michael_JM86

Member
Hi ActEd,

I am playing around with the Examiner's Model Solution Spreadsheet. When re-attempting the goal seek calculation (using the cell references the examiners provide in the Target Pricing worksheet) I am getting a negative solution... :/

Goal seek seems to give multiple solutions, and no matter how many times I re-run it I am not getting the answer of 2.3562 that the examiners give, even though I am using their spreadsheet and their exact goal seek parameters.

Please could you help me identify what I am doing wrong/ not doing...??

Many thanks,
Michael
 
Hi ActEd,

I am playing around with the Examiner's Model Solution Spreadsheet. When re-attempting the goal seek calculation (using the cell references the examiners provide in the Target Pricing worksheet) I am getting a negative solution... :/

Goal seek seems to give multiple solutions, and no matter how many times I re-run it I am not getting the answer of 2.3562 that the examiners give, even though I am using their spreadsheet and their exact goal seek parameters.

Please could you help me identify what I am doing wrong/ not doing...??

Many thanks,
Michael

Hi Michael
I've just had a go myself and I also get different answers each time!
I think the problem is that this is a discontinuous function. There is a "cliff edge" between 2.3636 and 2.3637. Input values in cell Y6 that are below this value give 100 and input values above it give 0. The algorithm used by Goal seek assumes that the function is continuous, so the results are not reliable here.
I found the cut-off point by trial and error, using an "up a bit / down a bit" method.
So, don't worry. You're not doing anything wrong!
 
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