Question 874979
let n be notebooks, p be packages of pencils, m be markers, then
Stan  n + 3p + 2m = $ 7.50
Jan  2n + 6p + 5m = $15.50
Fran  n + 2p + 2m = $ 6.25
let's subtract Fran from Stan and we get
p = $1.25
rewrite the three equations substituting for p
Stan  n + 3(1.25) + 2m =  7.50
Jan  2n + 6(1.25) + 5m = 15.50
Fran  n + 2(1.25) + 2m =  6.25
rewrite the three equations now with 2 variables
Stan  n + 2m = 3.75
Jan  2n + 5m = 8.00
Fran  n + 2m = 3.75
Note that Fran and Stan are the same now, so we use only one
Stan/Fran  n + 2m = 3.75
Jan       2n + 5m = 8.00
now we multiply Stan/Fran by 2
Stan/Fran 2n + 4m = 7.50
Jan       2n + 5m = 8.00
now subtract Stan/Fran from Jan
m = $.50
we now have p = $1.25 and m = $.50
let's substitute in Stan to get n
n + 3(1.25) + 2(0.50) = 7.50
n + 4.75 = 7.50
n = $2.75
therefore we have the following
n = $2.75, p = $1.25, m = $.50