Answer:
where's the number?
Step-by-step explanation:
Answer:

Step-by-step explanation:
For this case the solution flows at a rate of 2L/min and leaves at 1L/min. So then we can conclude the volume is given by 
Since the initial volume is 10 L and the volume increase at a rate of 1L/min.
For this case we can define A as the concentration for the salt in the container. And for this case we can set up the following differential equation:

Because at the begin we have a concentration of 8 gr/L and would be decreasing at a rate of 
So then we can reorder the differential equation like this:

We find the solution using the integration factor:

And then the solution would be given by:

And if we simplify this we got:

And after do the integral we got:

And using the initial condition t=0 A= 20 we have this:


So then we have this function for the solution of A:

And now replacinf t= 40 we got:

Three hundred fifty-one thousand five hundred twenty-eight and ninety-four thousandths
There are 12 inches in 1 foot, and each bracelet takes 6 inches
12 divided by 6 = 2
there can be 2 bracelets per foot of yarn
5 x 2 = 10 bracelets can be made
let me know if you have any further questions
:)