5×5 + 47 to the answer
2 answers:
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Answer:
Step-by-step explanation:
The greatest common divisor between 9 and 20 is 1, so we know the equation has a solution. A solution can be found either by inspection, or by applying Euclidean algorithm.
By inspection we just list some multiples of 9:
9, 18, 27, 36, 45, 54, 63, 72, 81, 90, 99
and also list some mutiples of 20:
20, 40, 60, 80, 100, 120
And so we see that we can find a multiple of 9 (81) which is 1 away from a multiple of 20 (80). Which is the solution given at the start.
For the Euclidean algorithm, we should divide the greatest of the two numbers, by the smallest one, and keep track of the remainder:
20 = 9 * 2 + 2
Then we divide 9 by the remainder we got, which is 2:
9 = 2 * 4 + 1
we would continue doing this until getting a remainder of 1 (which we just did). Finally we "solve" for 1, from the last equation:
9 - 2*4 = 1
And then we solve for 2 from the first equation, and plug that in into the previous equation:
20 - 9*2 =2
9 - ( 20 - 9*2)*4 = 1
which does give us the same solution:
Answer:
11.70% probability someone will spend no more than 30 minutes reading online national news reports.
Step-by-step explanation:
Problems of normally distributed samples can be 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 problem, we have that:
What is the probability someone will spend no more than 30 minutes reading online national news reports?
This is at most 30 minutes, so 30 or less minutes. This is the pvalue of Z when X = 30.
So
has a pvalue of 0.1170.
So there is a 11.70% probability someone will spend no more than 30 minutes reading online national news reports.