Dup= 72 miles
<span>ddown= 120 miles </span>
<span>v= riverspeed </span>
<span>rup= 32mph - v </span>
<span>rdown= 32mph + v </span>
<span>t both ways= t </span>
<span>d=r*t </span>
<span>d/r=t </span>
<span>t=ddown/rdown </span>
<span>t=dup/rup </span>
<span>dup/rup = ddown/rdown </span>
<span>(72)/(32-v)=(120)/(32+v) </span>
<span>3840-120v=2304+72v </span>
<span>1536=192v </span>
<span>v=8</span>
Answer: 40%
Step-by-step explanation: First determine whether the number increases or decreases. Since the number changes from 100 to 140 it's getting bigger, so it increases.
To find the percent increase, we use the following formula.
The amount of change is the difference between the two numbers which is 40 and we get this by subtracting 100 from 140. The original number will be the number that we started with which is 100.
140/100 simplifies to 0<em>.</em>4.
Finally, we want the percent increase so we write 0<em>.</em>4 as a percent by moving the decimal point 2 places to the right to get 40%.
Therefore, the percent increase is 40%.
Answer: K eeeeeeeeeeeeeeeeeeeeeeeeeee
Step-by-step explanation:
Answer:
With a 0.01 significance level and samples of 50 and 40 cofee drinkers, there is enough statistical evidence to state that the mean daily consumption of regular-coffee drinkers is less than that of decaffeinated-coffee drinkers.
The test is a one-tailed test.
Step-by-step explanation:
To solve this problem, we run a hypothesis test about the difference of population means.

The appropriate hypothesis system for this situation is:

Difference of means in the null hypothesis is:


![$$The calculated statistic is Z_c=\frac{[(4.35-5.84)-0]}{\sqrt{\frac{1.20^2}{50}+\frac{1.36^2}{40}}}=-5.43926\\p-value = P(Z \leq Z_c)=0.0000\\\\](https://tex.z-dn.net/?f=%24%24The%20calculated%20statistic%20is%20Z_c%3D%5Cfrac%7B%5B%284.35-5.84%29-0%5D%7D%7B%5Csqrt%7B%5Cfrac%7B1.20%5E2%7D%7B50%7D%2B%5Cfrac%7B1.36%5E2%7D%7B40%7D%7D%7D%3D-5.43926%5C%5Cp-value%20%3D%20P%28Z%20%5Cleq%20Z_c%29%3D0.0000%5C%5C%5C%5C)
Since, the calculated statistic
is less than critical
, the null hypothesis should be rejected. There is enough statistical evidence to state that the mean daily consumption of regular-coffee drinkers is less than that of decaffeinated-coffee drinkers.
Answer:
0.5728
Step-by-step explanation:
8*7.16/100 =0.5728