A man invested Tk. 26000 in 5% stock at 104. He sold the stock when the price rose to Tk. 120 and invested the sale proceeds in 6% stock. By doing this his income increased by Tk. 2500. At what price did he purchase the second stock?

Assuming that face value of the first stock = Tk. 100 as it is not given in the question.
Since it is a 5% stock, we can take the dividend per stock = Tk. 5
Market Value of the first stock = Tk. 104
Investment on the first stock = Tk. 26000
Number of stocks purchases = 26000/104 = 250
His total income from all these stocks = Tk. 250 × 5 = Tk. 1250
He sells each of these stocks at Tk. 120
ie, amount he earns = Tk. 120 × 250 = Tk. 30000
He invests this Tk. 30000 in 6% stock (here also face value is not given and hence take it as Tk. 100)
His new income = Tk. (1250 + 2500) = Tk. 3750
ie, By Tk. 30000 of investment, he earns an income of Tk. 3750
To get an income of Tk. 6, the investment needed = (30000 × 6)/3750
= Tk. 48.