Question

An amount of Rs. 4,000 is distributed into three investments at the rate of 7%, 8%

and 9% per annum respectively. The total annual income is Rs. 317.50 and the annual

income from the first investment is Rs. 5 more than the income from the second. Find

the amount of each investment using matrix algebra​

Answer 1

Step-by-step explanation:

et x,y and z be the investments at the rates of interest of 10%,12% and 15% per annum respectively.

Income from the first investment of Rs.x=Rs.10010x=Rs.0.1x

Income from the second investment of Rs.x=Rs.10012y=Rs.0.12y

Income from the first investment of Rs.x=Rs.10015z=Rs.0.15z

∴Total annual income=Rs.(0.1x+0.12y+0.15z)

⇒0.1x+0.12y+0.15z=1310 (∵ Total annual income=Rs.1310)

It is given that the combined income from the first two incomes is Rs.190 short of the income from the third.

∴0.1x+0.12y=0.15z−190

⇒−0.1x−0.12y+0.15z=190