Question 1095807

Solve using substitution method
For 2000 dollars are bought 15 notebooks and 12 markers. How much does 1 notebook and much does 1 marker cost, if 3 markers cost as much as 6 notebooks?

solving looks something like 
12x+15y=2000
6y=3x

Please explain thoroughly and step by step :)
<pre>This is very simple!
Let the price of a notebook be N, and that of a marker, M
Then we get: 15N + 12M = 2,000 ------- eq (i)
Also, {{{matrix(1,11, 3M, "=", 6N, "====>", M, "=", 6N/3, "=====>", M, "=", 2N)}}} ------ eq (ii)
15N + 12(2N) = 2,000 ------ Substituting 2N for M in eq (i)
15N + 24N = 2,000
39N = 2,000
N, or cost of a notebook = {{{highlight_green(matrix(1,3, "2,000"/39, "=", "$51.28"))}}}

Just multiply the cost of 1 notebook by 2 to get the cost of 1 marker.
That's all!! Nothing COMPLEX and/or CONFUSING.</pre>