A man purchased 150 pens at the rate of Rs.12 per pens. He sold 50 pens at a gain of 10%. The percentage gain at which he must sell the remaining pens so as to gain 15% on the whole outlay is.
A man purchased 150 pens at the rate of Rs.12 per pens. He sold 50 pens at a gain of 10%. The percentage gain at which he must sell the remaining pens so as to gain 15% on the whole outlay is. 1). $21\frac{1}{2}$% 2). 20% 3). 17% 4). $17\frac{l}{2}$%