The answer is B, because you will have to multiple 42 by 7 to see how much money he will have in 7 weeks and then you will have to subtract 8 × 8.25 to see how much money he spent on his vacation.
Please be a little specific.
Answer:
There is strong evidence that less than 87% of the orders are delivered in less than 10 minutes.
Decision rule: Reject the null hypothesis if (P-value < level of significance)
Test statistic z=-2.70
Decision: Reject the null hypothesis (0.003<0.010)
Step-by-step explanation:
In this question we have to test an hypothesis.
The null and alternative hypothesis are:

The significance level is assumed to be 0.01.
The sample of size n=80 gives a proportion of p=61/80=0.7625.
The standard deviation is:

The statistic z is then

The P-value is

The P-value (0.003) is smaller than the significance level (0.010), so the effect is significant. The null hypothesis is rejected.
There is strong evidence that less than 87% of the orders are delivered in less than 10 minutes.
Decision rule: Reject the null hypothesis if (P-value < level of significance)
Test statistic z=-2.70
Decision: Reject the null hypothesis (0.003<0.010)
Answer:
Decay
Step-by-step explanation:
We are given an equation 
We need to say about decay or growth of exponential function.
Exponential function: 
Where,
- a is initial value of exponential function.
- b is decay or growth of function
For decay: 0<b<1
For growth: b>1
Now we rewrite the equation into this form

Changes to

Here, b=0.5 < 1
Therefore, The given function would be decay.
Thus,
is deacy.