S.P. of Rs. 5000 stock`= Rs. (156/100 xx 5000)`

            `= Rs. 7800.`

Income from this stock` = Rs. (12/100 xx 5000)`

         `= Rs. 600.`

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

`:. (x xx 8/90) + (7800 - x) xx 9/108 = (600 + 70)`

`or 4x/45 + (7800 - x)/12`

`= 670`

`or 16x + 117000 - 15x`

`= (670 xx 180) or x = 3600.`

:. Money invested in 9% stock at 108 

`= Rs. (7800 - 3600)`

`= Rs. 4200.`

Let sum be x. Then,

S.I.` =(x xx 27/2 xx 4 xx 1/100)`

    `= (27x)/50`

:. Amount` = (x + (27x)/50)`

              `= (77x)/50`

`:. (77x)/50 = 2502.50 or x`

`= (2502.50 xx 50)/(77)`

`= 1625`

Hence, sum = Rs. 1625

S.I. for` 1 1/2` years = Rs. (1164 - 1008) = Rs 156.

S.I. for 2 years` = Rs.(156 xx 2/3 xx 2) = Rs. 208`

:. principal` = Rs. (1008 - 208) = Rs. 800`

Now, P = 800, T = 2 and S.I. = 208

:. Rate` = ((100 xx S.I)/(P xx T))`

  `= ((100 xx 208)/(800 xx 2))%`

` = 13%`

Let principal = P. Then, S.I. = P and Time = 8 years .

:. Rate` = ((100 xx P)/(P xx 8))%`

  `= 12.5%` per annum.

Let sum = P and original rate = R. Then,

`(P xx (R + 2) xx 3)/(100) - (P xx R xx 3)/(100)`

`= 360`

or 3 PR + 6P - 3PR

`= 36000 or 6P`

`= 36000 or P = 6000.

Hence, sum = Rs 6000.