Solution:
1. Set up the long multiplication.
2. Calculate 7 x 8, which is 56.
Since 56 is two-digit, we carry the first digit 5 to the next column.
3. Calculate 6 x 8, which is 48. Now add the carry digit of 5, which is 53.
Since 53 is two-digit, we carry the first digit 5 to the next column.
4. Calculate 5 x 8, which is 40. Now add the carry digit of 5, which is 45.
Since 45 is two-digit, we carry the first digit 4 to the next column.
5. Calculate 4 x 8, which is 32. Now add the carry digit of 4, which is 36.
Since 36 is two-digit, we carry the first digit 3 to the next column.
6. Bring down the carry digit of 3.
7. Calculate 7 x 5, which is 35.
Since 35 is two-digit, we carry the first digit 3 to the next column.
8. Calculate 6 x 5, which is 30. Now add the carry digit of 3, which is 33.
Since 33 is two-digit, we carry the first digit 3 to the next column.
9. Calculate 5 x 5, which is 25. Now add the carry digit of 3, which is 28.
Since 28 is two-digit, we carry the first digit 2 to the next column.
10. Calculate 4 x 5, which is 20. Now add the carry digit of 2, which is 22.
Since 22 is two-digit, we carry the first digit 2 to the next column.
11. Bring down the carry digit of 2.
12. Calculate 7 x 2, which is 14.
Since 14 is two-digit, we carry the first digit 1 to the next column.
13. Calculate 6 x 2, which is 12. Now add the carry digit of 1, which is 13.
Since 13 is two-digit, we carry the first digit 1 to the next column.
14. Calculate 5 x 2, which is 10. Now add the carry digit of 1, which is 11.
Since 11 is two-digit, we carry the first digit 1 to the next column.
15. Calculate 4 x 2, which is 8. Now add the carry digit of 1, which is 9.
16. Calculate 7 x 3, which is 21.
Since 21 is two-digit, we carry the first digit 2 to the next column.
17. Calculate 6 x 3, which is 18. Now add the carry digit of 2, which is 20.
Since 20 is two-digit, we carry the first digit 2 to the next column.
18. Calculate 5 x 3, which is 15. Now add the carry digit of 2, which is 17.
Since 17 is two-digit, we carry the first digit 1 to the next column.
19. Calculate 4 x 3, which is 12. Now add the carry digit of 1, which is 13.
Since 13 is two-digit, we carry the first digit 1 to the next column.
20. Bring down the carry digit of 1.
21. Calculate 36536 + 228350 + 913400 + 13701000, which is 14879286
22. Place the decimal.
45.67 has 2 decimal places, and 32.58 has 2 decimal places.
Therefore, the answer should have 2 + 2 = 4 decimal places.
23. Therefore, 45.67 x 32.58 = 1487.9286.
1487.92861487.9286
Done!
Answer:
a) 0.047
b) 50% probability that the sample proportion of smart phone users is greater than 0.33.
c) 33.39% probability that the sample proportion is between 0.19 and 0.31
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
Normal probability distribution
When the distribution is normal, we use the z-score formula.
In a set with mean
and standard deviation
, the zscore of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
Central Limit Theorem
The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean
and standard deviation
, the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean
and standard deviation
.
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean
and standard deviation 
In this question, we have that:

a) What would the standard deviation of the sampling distribution of the proportion of the smart phone users be?

b) What is the probability that the sample proportion of smart phone users is greater than 0.33?
This is 1 subtracted by the pvalue of Z when X = 0.33. So

By the Central Limit Theorem



has a pvalue of 0.5
1 - 0.5 = 0.5
50% probability that the sample proportion of smart phone users is greater than 0.33.
c) What is the probability that the sample proportion is between 0.19 and 0.31?
This is the pvalue of Z when X = 0.31 subtracted by the pvalue of Z when X = 0.19. So
X = 0.31



has a pvalue of 0.3354
X = 0.19



has a pvalue of 0.0015
0.3354 - 0.0015 = 0.3339
33.39% probability that the sample proportion is between 0.19 and 0.31
Take 15% of 400, or 0.15 x 400
0.15 x 400 = 60
However, $60 is only the 15%.
Now, take away 60 from 400.
400 - 60 = 340.
So $340 went towards the trip.
It’s a little blurry can’t really read it