Relation between CPI and TCPI

[anurag1720]

Hi,

I want to start a thread for discussing relation between CPI and TCPI. I came across an exam question where I was asked to demonstrate relation between CPI and TCPI. So the question goes if the project is 50% complete and current CPI is 0.75. What is the TCPI? According to my calculations which I am demonstrating below the answer comes out to be 1.51 but the correct answer is 1.25.

My Answer:
Since project is 50% complete EV = 0.5 * BAC

CPI = 0.75 => AC = (EV/0.75) = (0.5 * BAC)/(0.75) = 0.67 * BAC

TCPI = (BAC-EV)/(BAC-AC) = (BAC - 0.5 * BAC)/(BAC - 0.67 * BAC) = 1.51

[barnita_n]

My Calculation:

EV = .5BAC

EV/AC= .75 , AC = EV/.75=.5BAC/.75=BAC*.666

TCPI = BAC-EV/BAC-AC = > (BAC -.5BAC ) / (BAC--.666BAC)

TCPI = .5/.4 = 1.25

[nazrulq]

1st Answer is also correct which is 1.51.
Since its a rounded up number .4
Answer could be 1.25
PMP Exam question answer should be accurate.