Easy
5 notebooks and 1 pen cost Rs 315. 5 notebooks and 2 pens cost Rs 330. What is the cost of a notebook?
Explanation
Explanation
Subtracting the two equations: (5 notebooks+2 pens) - (5 notebooks+1 pen) = 330-315, so 1 pen = Rs 15. Then 5 notebooks = 315-15 = 300, so one notebook = Rs 60.
PRO TIP
Re-check your working by substituting the answer back into the original question.