The test statistic (Z) is 2.5767, and the p-value of the test is 0.009975. The null hypothesis suggests that the smoking rate among students has not changed, while the alternative indicates otherwise. The z-statistic for the sampled proportion is computed, yielding z ≈ 2.5767. As we investigate whether the smoking percentage has shifted over the preceding five years, the two-tailed p-value is found to be 0.009975. This result is significant at a 99% confidence level, demonstrating substantial evidence that the percentage of smoking students has changed.
Answer:
The original cost amounts to $10
Step-by-step explanation:
Let us denote the cost as x
where Price = x + (0.5x) = 1.50x
Now, the price after reduction is 20% of 1.50x
which is 0.3x 
This leads to the equation 1.50x - 0.3x = 12
resulting in 1.2x = 12
which gives us x = 10
thus, the cost is $10
