Answer:
13 pencils.
Step-by-step explanation:
Let x be the pens and y be the pencils
Given:
Brian purchased pens for 75 cents each and pencils for 40 cents each he bought total of 22 writing utensils for $11.95.
Total pens and pencils is 22
So,
----------------(1)
And he bought all utensils for $11.95. and each pen for 75 cents and pencils for 40 cents.
------------(2)
solve equation 1 and equation 2 for x and y.
From equation 1.

----------------(3)
put y value in equation 2.







Now substitute x value in equation 3.


So, he buy 13 pencils.
The GCF of 18 and 30 is 6
Answer:

So it would takes approximately 6.9 hours to reach 32 F.
Step-by-step explanation:
For this case we have the following differential equationÑ

We can reorder the expression like this:

We can use the substitution
and
so then we have:

IF we integrate both sides we got:

If we apply exponential in both sides we got:

And if we replace w = u-T we got:

We can also express the solution in the following terms:

For this case we know that
since w ehave a cooloing,
, we have this model:
And if we want that the temperature would be 32F we can solve for t like this:



If we apply natural logs on both sides we got:


So it would takes approximately 6.9 hours to reach 32 F.
Step-by-step explanation:
<h3>hope it helps.</h3><h3>stay safe healthy and happy.</h3>