equation 1: 2N+3P=14.50
equation 2: 1N +2P =7.50
multiply equation 2 by 2 so that N is same as equation 1
1N+2P=7.50 x 2 = 2N+4P = 15.00
subtract equation 1 from new equation
2N+4P = 15.00 - 2N+3P=14.50 = 1P = 0.50
so 1 pen cost 0.50
replace 0.50 for P in equation 1:
2N+3P=14.50 =
2N +3(0.50) = 14.50
2N +1.50 =14.50
2N = 13.00
N=13.00/2 = 6.50
notebook cost 6.50
check:
2(6.50) + 3(0.50) = 13 +1.50 = 14.50
1(6.50) +2(0.50) =6.50 + 1.00 = 7.50
both equations work
Pens cost 0.50 each
notebooks cost 6.50 each
