Cost of a dozen pens is Rs.180 and cost of 8 ball pens is Rs.56. Find the ratio of the cost of a pen to the cost of a ball pen.
Cost of a dozen pens (12 pens) = Rs.180
Cost of 1 pen = 180/12 = Rs.15
Cost of 8 ball pens = Rs.56
Cost of 1 ball pen = 56/8 = Rs.7
Ratio of cost of one pen to that of one ball pen = 15/7 = 15 : 7
