S2010 Q4 First Principles

Discussion in 'CT5' started by MoleMan, Sep 7, 2018.

  1. MoleMan

    MoleMan Member

    Hi,

    When attempting to do this question I converted to monthly annuities for the calculation and the result differs slightly.

    Calculation as follows (from first principles):

    Number of memberships n = 120
    Monthly fee per person f = 240 / 12 = £20
    Monthly discount factor v = [1 + 0.06]^[-1 / 12] = 0.995156
    Monthly survival probability p = [1 - 0.01]^[1 / 12] = 0.999163
    Monthly one-year annuity a = 1 + pv + [pv]^2 + … + [pv]^11 = [1 - (pv)^12] / [1 - pv] = 11.632312

    Expected Present Value E = fna(1 + 0.8[pv]^12 + 0.64[pv]^24) = 64,362.03

    The question states that premiums are payable monthly in advance and premiums cease immediately on the death of the member i.e. no payments in the month following death.

    Would my answer receive full credit or is it a requirement to use the one-year-annuity-due-payable-monthly method described in the examiners’ report?

    Not sure where the factor 11/24 the examiner has used comes from; first principles seem far more intuitive.

    Best regards,

    MoleMan
     
  2. Mohit Gulati

    Mohit Gulati Active Member

    since examiner used the approximate formula and in that formula the factor 11/24 is given . the formula is given in actuarial table
    on page 36.

    (a dot dot x:n - (m - 1)/2m (1 - (Dx+n/Dx))

    so if m is 12 so (12-1)/12*2 = 11/24
     
    Last edited: Sep 7, 2018
  3. MoleMan

    MoleMan Member

    Thanks Mohit,

    Still worried about losing marks for answering differently than the examiner intends.
     
  4. Mohit Gulati

    Mohit Gulati Active Member

    no i donot think, they will disregard this approach, as long as final answer is correct,
     

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