Two variables vary inversely if their product is constant (does not change). The variables w and t vary inversely so their product wt = k were k is a constant. Solving this for t we get t=k/w
We are told that w = 4 and t = 1/5 so we know their product wt = (4)(1/5) = 4/5. This is what I called k before.
Therefore the relationship between w and t can be modeled by t = (4/5) / w. That is, t = 4 / 5w
Further, when w = 9, we find t by substituting 9 for w in the equation just found and obtain: t = 4 / [(5)(9)] = 4/45. That is, when w = 9, t = 4/45.
This mean choice D is the correct answer.
Use division: amount of money/cost of one cartridge=140/14=10
Answer:
Step-by-step explanation:
we have the following differential equations

by differentiating the second equation we have

and we replace dx/dt in the first equation

and by using the characteristic polynomial

the solution is

and to compute x(t) we have
![\frac{dx}{dt}=-2Acos(2t)-2Bsin(2t)\\\\\int dx = \int[-2Acos(2t)-2Bsin(2t)]dt\\\\x(t)=-Asin(2t)+Bcos(2t)](https://tex.z-dn.net/?f=%5Cfrac%7Bdx%7D%7Bdt%7D%3D-2Acos%282t%29-2Bsin%282t%29%5C%5C%5C%5C%5Cint%20dx%20%3D%20%5Cint%5B-2Acos%282t%29-2Bsin%282t%29%5Ddt%5C%5C%5C%5Cx%28t%29%3D-Asin%282t%29%2BBcos%282t%29)
and if we use x(0)=4 and y(0)=3, we can calculate the constants A and B

I hope this is useful for you
regards
Try A, $5000. I did 550 divided by 11, which is 50, then multiplied by 10 to find 10%, then multiplied the 10%, which was 500, by 10 to get 100% which is 5,000