Answer a maths question?

[Andy Charles]

Hi all,

Mark saved 20% from his rent. John rent is 1000 dollars more than Marks and saves only 18% from his rent, that is 120 dollars more than Mark saves. How much is John rent?
Please looking for an answer quickly.

Thanks a lot.
Andy Charles

[Guest]

Suppose that John rent is x dollars.

John rent is 1000 dollars more than Mark's
So Mark's rent is x-1000

Mark saves (x-1000)*0.2 = 0.2x - 200
John saves 0.18x / 18% from x
Savings of John are $120 more than Mark's
so
0.18x = 0.2x - 200 + 120
0.18x - 0.2x = - 80
0.02x = 80
x=80/0.02 = 4000

[Guest]

Do you have any questions?
Is the solution clear?

[anmath14]

Given three points p=(2,1,3), q=(1,0,1) and r=(2,-1,1). Find the Cartesian equation of the plane containing those points.

[HallsofIvy]

Anmath14, please do not "hijack" a person's thread to ask a different question. Start your own thread. I have started a thread for you under the title "Anmath14's question".