The market value of a 10.5% stock, in which an income of Rs. 756 is derived by investing Rs. 9000, brokerage being 1/4%, is:

For an income of Rs. 756, investment = Rs. 9000. 

For an income of  $Rs.\frac{21}{2}$,  investment = $Rs.\frac{9000}{756}\times \frac{21}{2}$ = Rs. 125.

For a Rs. 100 stock, investment = Rs. 125.

Market value of Rs. 100 stock =  $Rs.125-\frac{1}{4}$= Rs. 124.75