In question 10 attached, with regards to the pension benefit, why does it reduce to the summation of two deferred monthly annuities in advance (a_55 + a_50) ?
My equation of value would be (the annuities's are all monthly in advance): 10000 times the joint life annuity deferred for ten years plus 5000 times the last survivor annuity deferred for ten years. Using the formula for the last survivor annuity this reduces to 5000 times a deferred whole life annuity for x plus a whole life for y minus the joint annuity for x and y.
But this is wrong and i do not understand why the answer is only the sum of the deferred annuity for x and y (where did the joint part go?)
I hope my question makes sense :(
Thank you (in advance) <3