Answer:
(B) 30% decrease
Step-by-step explanation:
We proceed with the calculation as follows:
For September 1, 1992
For simplicity purpose, let us assume the total number of construction workers in 1992 is 100.
Since, construction workers’ unemployment rate in 1992 = 16%
Therefore;
Number of unemployed construction workers in 1992 = 16
For September 1, 1996
Since the number of construction workers was 20 percent greater on September 1, 1996, than on September 1, 1992, we have:
Total number of construction workers in 1996 = 100 × (1 + 0.2) = 120
Since, construction workers’ unemployment rate in 1996 = 9%
Therefore;
Number of unemployed construction workers in 1996 = 120 × 9% = 10.8
Calculation of change in the number of unemployed construction workers between September 1, 1992 and September 1, 1996
Change in number of unemployed construction workers = 10.8 - 16 = – 5.2
This implies a decrease of 5.2. This will be used is absolute term to calculate the percentage as follows:
Percentage of Change number of unemployed construction workers = (5.2 ÷ 16) × 100 = 32.5% decrease
Since 32.5% is approximately 30% which is the closest in the question, the approximate percentage change in the number of unemployed construction workers between September 1, 1992 and September 1, 1996 is therefore a 30% decrease.
Note:
In real life, there cannot be 10.8 or 5.2 unemployed construction workers. We just used the figures as a hypothetical example without rounding to get for simplicity purpose.