**Ans . **

Rs. 6480.,Rs. 4680,Rs. 5440

**Explanation :**(i) Cost of Rs. 100 stock = Rs. 90

Cost of Rs. 7200 stock = Rs. (90/100 * 7200 ) = Rs. 6480.

(ii) Cost of Rs. 100 stock = Rs. (100+4)

Cost of Rs. 4500 stock = Rs. (104/100 * 4500 ) = Rs. 4680

(iii) Cost of Rs. 100 stock = Rs. (100-15)

Cost of Rs. 6400 stock = Rs. (85/100 * 6400 ) = Rs. 5440.

**Ans . **

Rs. (215/2),Rs. 3440

**Explanation :**Cash required to purchase Rs. 100 stock = Rs (107+(1/2)) = Rs. (215/2).

Cash required to purchase Rs. 100 stock = Rs [(215/2)*(1/100)*3200] = Rs. 3440

**Ans . **

Rs. (383/4),Rs 2298

**Explanation :**By selling Rs. 100 stock , cash realised = Rs. [(100-4)-(1/4)] = Rs. (383/4).

By selling Rs. 2400 stock, cash realised = Rs. [(383/4)*(1/100)*2400] = Rs 2298.

**Ans . **

Rs. 200

**Explanation :**Income from Rs. 100 stock = Rs. 8.

Income from Rs. 2500 = Rs. [(8/1000*2500) =Rs. 200.

**Ans . **

Rs. 500

**Explanation :**By investing Rs. 136, income obtained = Rs. 10.

By investing Rs. 6800, income obtained = Rs. [(10/136)*6800] = Rs. 500.

**Ans . **

7(1/2) % stock at 105 is better

**Explanation :**Let the investment in each case be Rs. (105*94).

Case I : 7(1/2) 5 stock at 105:

On investing Rs. 105, income = Rs. (15/2).

On investing Rs. (105*94), income = Rs. [(15/2)*(1/105)*105*94] = Rs 705.

Case II : 6(1/2) % stock at 94:

On investing Rs. 94, income = Rs. (13/2).

On investing Rs. (105*94), income = Rs. [(13/2)*(1/94)*105*94] = Rs. 682.5.

Clearly, the income from 7(1/2) % stock at 105 is more.

Hence, the investment in 7(1/2) % stock at 105 is better.

c**Ans . **

Rs. 912

**Explanation :**Cost of 1 share = Rs. [(10-(3/4)) + (1/4)] = Rs. (19/2).

Cost of 96 shares = Rs. [(19/2)*96] = Rs. 912.

**Ans . **

Rs. 165, 6.2 %

**Explanation :**Cost of 1 share = Rs. [25+5+1/4)] = Rs. (121/4).

Cost of 88 shares = Rs.[(121/4)*88] = Rs. 2662.

Investment made = Rs. 2662.

Face value of 88 shares = Rs. (88*25) = Rs. 2200.

Dividend on Rs. 100 = (15/2).

Dividend on Rs. 2200 = Rs. [(15/20*(1/100)*2200] = Rs. 165.

Income derived = Rs. 165.

Rate of interest on investment = [(165/2662)*100] = 6.2 %.

**Ans . **

Rs. 22.50

**Explanation :**Suppose he buys each share for Rs. x.

Then, [25*(9/100)] = [x*(10/100)] or x = Rs. 22.50.

Cost of each share = Rs. 22.50.

**Ans . **

Rs. 4200.

**Explanation :**S.P of Rs. 5000 stock = Rs. [(156/100)*5000] = Rs. 7800.

Income from this stock = Rs. [(12/100)*5000] = Rs. 600.

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

[x*(8/90)] + (7800-x) * (9/108) = (600+7)

(4x/45) + [(7800-x)/12] = 670 -->16x + 117000-15x = (670*180) --> x = 3600.

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

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