Number of shares = \(\frac{4500}{10}\) = 450
Income from 2% stock = Number of shares x face value x Rate of dividend
= 450 x 10 x \(\frac{2}{100}\)
= Rs 90
Selling price of 450 shares = 450 x 23 = Rs 10,350
Number of shares bought in 10% stock
= \(\frac{Selling\,price\,of\,450\,shares\,at\,Rs\,23}{Market\,value}\)
= \(\frac{10350}{18}\)
= Rs 575
Income, from 10% stock = No of shares x face value x Rate of dividend
= 575 x 25 x \(\frac{10}{100}\)
= 575 x \(\frac{10}{4}\)
= Rs 1437.5
= Rs 1437.50
Charge in his income = Rs 1437.50 – Rs 90 = Rs 1347.50