Answer with Step-by-step explanation:
Let x be the cost of 1 pen and y be the cost of 1 pencil
8 pens and 7 pencils cost $3.37 while 5 pens and 11 pencils cost $3.10
8x+7y= 3.37 -----------------(1)
and 5x+11y= 3.10 -----------------(2)
equation (1)×5-equation(2)×8
5(8x+7y)-8(5x+11y)=3.37×5-3.10×8
40x+35y-40x-88y= -7.95
-53y = -7.95
y= 0.15
Putting y=0.15 in equation (1), we get
8x+7×0.15=3.37
8x+1.05=3.37
8x=2.32
x=0.29
Hence, Cost of 1 pen=$ 0.29
Cost of 1 pencil= $ 0.15