C.P. of 150 calculators = 150 x 250 = Rs. 37500
∴ Total C.P. = 37500 + 2500 = Rs. 40000
Marked price of 150 calculator = 150 x 320 = Rs. 48000
Selling price after discount = 48000 x 95 / 100 = Rs. 45600
∴ percentage profit = [(45600 - 40000) / 40000] x 100 = 14%