need help on a simple question.

any helps is appreciated. Please find the question attached

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- May 27th 2011, 11:20 AMmathieWeighted factors
need help on a simple question.

any helps is appreciated. Please find the question attached

Attachment 21607 - May 27th 2011, 02:40 PMpickslides
Hi there mathie,

Please don't double post.

Your excel sheet makes sense to me. But the question may lack some context. - May 27th 2011, 03:06 PMemakarov
Let $\displaystyle n_a$ and $\displaystyle n_b$ be the non-working years of A and B, respectively, and let $\displaystyle t_a$ and $\displaystyle t_b$ be the total years (non-working plus working) of A and B. Then the share of the non-working years for A is $\displaystyle x_a = n_a / t_a$, and the share for B is $\displaystyle x_b = n_b / t_b$. Finally, the total share is $\displaystyle x = (n_a+n_b) / (t_a+t_b)$.

Thus, $\displaystyle x=(x_at_a+x_bt_b)/(t_a+t_b)=x_a\cdot t_a/(t_a+t_b)+x_b\cdot t_b/(t_a+t_b)$.