Answer:
7 weeks
Explanation:
in total there are 40 unemployed people in the economy, and the average duration of unemployment will be:
[(10 unemployed x 4 weeks) + (30 unemployed x 8 weeks)] / 40 unemployed = (40 + 240) / 40 = 280 / 40 = 7
*I used an adjusted expected value formula = ∑ (unemployed x unemployment length) / total unemployed