Stock = Rs.9000
FV =Rs.100
Dividend Rate = 7%
Income on 7% stock =\(\frac { \text {stock} }{ 100 } \)x FV x Rate percentage
=\(\frac { 9000 }{ 100 } \times 100\times \frac { 7 }{ 100 } \) = Rs.630    ...(1)
Cost of price of one share = 80
Sale proceeds = \(\frac { \text {stock} }{ 100 } \) x Cost Price
=\(\cfrac { 9000 }{ 100 } \)x 80 =7200
Investment = Rs.7200
Market Price = Rs.120
Dividend Rate =15%
Income =\(\frac {\text { Investment} }{ \text {Market Price } }\)x Dividend Rate
=\(\frac { 7200 }{ 120 } \)x15=Rs.900 .....(2)
Change in income = 930 - 630 = Rs.270

Stock = Rs.5000
FV = Rs.100
Dividend Rate = 20%
Income from 20% stock = \(\frac { Stock }{ Fv } \times Rate\)
= \(\frac { 5000 }{ 100 } \) x 20
= Rs.1000
Selling price of one share = 100+62-2 =160   ..(1)
Sale proceeds= \(\frac { Stock }{ Fv } \)x S.P.of one share
= \(\frac { 5000 }{ 100 } \) x 20
= Rs.8000
Investment = Rs.8000
Market Price = 100 - 22 + 2 = 80
Dividend Rate = 15%
\(\therefore\) Income from 15% stock = \(\frac {\text { Investment} }{ \text {Market Price } }\) x Rate
= \(\frac { 80,000 }{ 80 } \) x 15 = Rs.1500   ....(2)
From (1) and (2)
Change in his income =1500-1000
= Rs.500

Let the amount invested in each stock be Rs.x
For 12% Stock
Investment =Rs.x
Purchased Price = 89+1 = 90
Income=\(\frac {\text { Investment} }{ \text {Purchase Price } }\) x Dividend Rate
=\(\frac { x }{ 90 } \times 12=\frac { 2x }{ 15 } \)   ...(1)
For 8% Stock
Investment = Rs.x
market Price = 95+1= 96
Dividend Rate = 8%
Income=\(\cfrac { x }{ 96 } \times 8 =\cfrac { x }{ 12 } \)  ...(2)
Difference in income = Rs.120
From (1) and (2),  \(\cfrac { 2x }{ 15 } -\cfrac { x }{ 12 } \) = 120
\(x\left( \cfrac { 2 }{ 15 } -\cfrac { 1 }{ 12 } \right) \) = 120
\(x\left( \cfrac { 8-5 }{ 60 } \right) \) = 120
\(\cfrac { 3x }{ 60 } \) = 120
\(\Rightarrow\) x = \(\cfrac { 120\times 60 }{ 3 } \) = Rs.2400
Hence, investment in each stock is Rs.2400

Stock = Rs.8000
FV = Rs.100
Dividend Rate = 7%
Income = \(\frac { Stock }{ FV } \times Dividend \ Rate=\frac { 8000 }{ 100 } \times 7\) = Rs.560  ....(1)
Selling price of one share=Rs.96
Sale proceeds = \(\frac { Stock }{ FV } \)x S.P of one share = \(\frac { 8000 }{ 100 } \) x 96 = Rs.7680
Given that the income on 10% stock
= 560+80 = 640
FV = Rs.10
Income = \(\frac { \text {Investment }}{ \text {Purchase Price } }\) x Dividend Rate
640 = \(\frac { 7680 }{\text { Purchase Price } }\) x 10
Purchase Price = \(\frac { 7680 }{ 640 } \) x 10 = Rs.120
Hence, purchase price of 10% stock=Rs.120

Number of preference shares = 1000
Preferential stock = 1000 X 100 = Rs.1,00,000
Ordinary shares = 4000
Ordinary shares = 4000 x 100 = Rs.4,00,000
Total dividend = Rs.40,000
Dividend on preference share=\(\frac { 1,00,000 }{ 100 } \) x 6 = Rs.6,000
Dividend on ordinary shares=Total dividend-dividend on preference shares
= 40,000-6000
=Rs.34,000
Sundar's income on preference shares
= No.of shares X FV XRate percentage
=100 x 100 x \(\frac { 6 }{ 100 } \)
=Rs.600         ...(1)
Sundar's income on ordinary shares
=\(\frac { 2500 \times 100 }{ 4,00,000 } \) x 34,000=Rs.1700   ..(2)
\(\therefore\)Sundar's total income = 600+1700
= Rs.2300