productivity - 經濟

in 2007 a firm produced 60000 calculators, employing 80 workers

each of whom worked 8 hours per day.

in 2008 the ame firm produced 76500 calactors, employing 85 workers

each of whom worked 10 hours per day.

between 2007 and 2008 productiviy at firm

a) decreasd by 4 percent
b) remained constant
c) increased by 8.33 percent
d) increased by 27.5 percent

我作法是先設 y= Y/L

dy/y = dY/Y - dL/L
= (76500-60000)/60000 - (85*10*365-80*8*3650/(80*8*365)

= 0.275 - 0.3288125 = -0.05335 <0 (沒這個答案)

我想問一下 我究竟錯在哪裡 計算結果明明是衰退

對於答案是c 其實我頗不解的

THANKS

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