Answer:
20
Step-by-step explanation:
Charle would have spent that much because one pound is 2.50
15 divided by 6=2.50
2.50x8=20
Descriptions 1, 2, 3, and 5 are accurate, though 5 is ambiguous.
_____
Description 4 goes with (7x)² = 49x², not 7x².
Description 6 goes with 5·8 + x² + (2x + 8) = x² +2x +48, not 40x² +100x +40.
The description for 5 is accurate, but could also be applied to y² + 3(y - 4), which is why it can be considered to be ambiguous. There are a number of ways to resolve the ambiguity, but they were not used here.
Answer:
$ 7.9
Step-by-step explanation:
Amount of bill = $52.87 = $52.9
Amount of tip = 15% of $52.9
Answer:
Step-by-step explanation:
If we assume that the number of arrivals is normally distributed and we don't know the population standard deviation, we can calculated a 95% confidence interval to estimate the mean value as:
where x' is the population mean value, x is the sample mean value, s is the sample standard deviation, n is the size of the sample, is equal to 0.05 (it is calculated as: 1 - 0.95) and is the t value with n-1 degrees of freedom that let a probability of on the right tail.
So, replacing the mean of the sample by 49, the standard deviation of the sample by 17.38, n by 10 and by 2.2621 we get:
Finally, the interval values that she get is: