Two salesmen A and B together sold 30 pens. A sold all his pens at the same rate, so does B. Though A sold his pens at a
different rate than at a rate B sold, they both receive the same amount after selling all their pens. If A had sold his pens
at the rate at which B sold, he would have received Rs.320. If B had sold his pens at the rate at which A sold, he would
have received Rs.245. At what price did B sell each of his pens?