A man sells Rs.5000, 12 % stock at 156 and uinvests the proceeds parity in 8 % stock at 90 and 9 % stock at 108. He hereby increases his income by Rs. 70. How much of the proceeds were invested in each stock?

S.P of Rs. 5000 stock =  $Rs.\frac{156}{100}*5000$= Rs. 7800. 

Income from this stock =  $Rs.\frac{12}{100}*5000$ = Rs. 600.  

Let investment in 8 % stock be x and that in 9 % stock = (7800 - x).

Therefore,  

$x*\frac{8}{90}+7800-x*\frac{9}{108}=600+70$  

$\frac{4x}{45}+\frac{7800-x}{12}=670\iff x=3600$ 

Therefore,  Money invested in 8 % stock at 90 = Rs. 3600.

Money invested in 9 % at 108 = Rs. (7800-3600) = Rs. 4200.