Answer: A) 3(10 - 5y) + 6y =12
Step-by-step explanation:
As per the question , the given system of linear equation :
Here , To solve the system of equations using substitution , Johanna isolates x in the second equation and writes
As per the substitution method , the next step is to substitute the isolated value of 'x' in first equation , thus the next step will become
Hence, the correct option is A) 3(10 - 5y) + 6y =12
Answer:
At least 75% of these commuting times are between 30 and 110 minutes
Step-by-step explanation:
Chebyshev Theorem
The Chebyshev Theorem can also be applied to non-normal distribution. It states that:
At least 75% of the measures are within 2 standard deviations of the mean.
At least 89% of the measures are within 3 standard deviations of the mean.
An in general terms, the percentage of measures within k standard deviations of the mean is given by .
In this question:
Mean of 70 minutes, standard deviation of 20 minutes.
Since nothing is known about the distribution, we use Chebyshev's Theorem.
What percentage of these commuting times are between 30 and 110 minutes
30 = 70 - 2*20
110 = 70 + 2*20
THis means that 30 and 110 minutes is within 2 standard deviations of the mean, which means that at least 75% of these commuting times are between 30 and 110 minutes