Answer:
a) The correct option is C: 4x
b) The correct option is B: 2x
Step-by-step explanation:
a) Usually when we have a real number multiplying a variable, we do not need to write the multiplication symbol.
So instead of writing:
4×x
We can write:
4x
And this will be equivalent.
Then in this case the correct option is C.
b) We know that if we have the multiplication of A by n, this will be equivalent to add A n times.
Then if we have the sum of A, for example, 4 times, we have:
A + A + A + A
And this can be written as 4*A
In this case, we have the expression x + x.
So we are adding x two times, then this can be written as: 2*x, or, as we said earlier, this also can be written as 2x.
Then the correct option is option B.
Answer:
A. 3t = 24
Step-by-step explanation:
$24 is the total amount spent.
$3 is the price per ticket.
so to get the number of tickets, t, you need the equation 3t = 24.
Answer:
$16
Step-by-step explanation:
Let his weekly allowance = x
Amount spent playing golf = x / 2
Amount earned for cleaning car = $4
Final amount at hand = $12
Mathematically ;
x/2 + 4 = 12
x/2 = 12 - 4
x/2 = 8
x = 2 * 8
x = $16
Weekly allowance = $16
Answer:
The percentile is calculated with the following probability:

And using the z score we got:

So then we can conclude that 31 represent approximately the percentile 81 on the distribution given
He scored better than about 80.98 % of all MCAT takers.
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Let X the random variable that represent the scores of a population, and for this case we know the distribution for X is given by:
Where
and
And for this case we have a score of 31
The percentile is calculated with the following probability:

And using the z score we got:

So then we can conclude that 31 represent approximately the percentile 81 on the distribution given
He scored better than about 80.98 % of all MCAT takers.