q + n = 91
q +n -n =91-n
q= 91-n
.25q +.05n = $14.55
.25(91-n)+.05n = $14.55
22.75-.25n+ .05n= $14.55
22.75 -.20n =14.55
22.75-22.75-.20n=14.55-22.75
-.20n=-8.2
-.20n/-.20n= -8.2/-.20n
n= 41
q + 41 = 91
q +41 -41 = 91-41
q = 50
CHECK
.25(50) + 0.05(41) = $14.55
12.50 + 2.05 = $14.55
$14.55 = $14.55