Question 518876
Price per wirebound graph-paper notebook = $2.60
Price per college-ruled notebook = 2.45$
Number of wirebound graph-paper notebook sold = x  
Number of college-ruled notebook sold = 75-x
Total Amount = 191.25

2.60*(Number of WG notebook) + 2.45*(Number of CR notebook) = Total
2.60*(x) + 2.45*(75-x) = 191.25
2.60x+183.75-2.45x=191.25
2.60x-2.45x=191.25-183.75
0.15x=7.5
0.15x/0.15=7.5/0.15
x=50

Number of wirebound graph-paper notebook sold = x = 50  
Number of college-ruled notebook sold = 75-x = 75-50 = 25

Check
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50*2.60 + 25*2.45 = 191.25
130+61.25=191.25
191.25=191.25