<u>Let's solve this problem step-by-step</u>
<u>Let's set</u>:
2x + 6y = 36 -- equation 1
x + 4y = 20 -- equation 2
(equation 2) * 2
2x + 8y = 40 -- equation 3
(equation 3) - (equation 1)
2y = 4
y = 2 -- equation 4
Plug (equation 4)'s value of y into (equation 2)
x + 4(2) = 20
x = 20 - 8
x = 12
<u>Thus x = 12 and y = 2</u>
<u>Let's check, by substituting these values</u>
<u>Answer: x = 12 and y = 2</u>
Hope that helps!
Answer:
19.77% of average city temperatures are higher than that of Cairo
Step-by-step explanation:
Problems of normally distributed samples are solved using 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.
In this question, we have that:
What percentage of average city temperatures are higher than that of Cairo?
This is 1 subtracted by the pvalue of Z when X = 21.4.
has a pvalue of 0.8023
1 - 0.8023 = 0.1977
19.77% of average city temperatures are higher than that of Cairo