. Susan invested certain amount of money in two schemes A and B


Susan invested certain amount of money in two schemes A and B , which offer interest at the rate of 8% per annum and 9% per annum, respectively. She received Rs. 1860 as annual interest. However, had she interchanged the amount of investments in the two schemes, she would have received Rs. 20 more as annual interest. How much money did she invest in each scheme?

A: Rs. 13000 in scheme A, Rs. 12000 in scheme B

B: Rs. 12000 in scheme A, Rs. 10000 in scheme B

C: Rs. 11000 in scheme A, Rs. 10000 in scheme B

D: Rs. 10000 in scheme A, Rs. 13000 in scheme B

Best Answer

Explanation

Let the total investment made by susan be P1=x in A and P2=y in B.

The rate of interest in A is R1=8%and for B is R2=9%.

We know the formula to find interest after investment in A will be formula

And the annual interest for the investment in B will be annual interest

The total interest for a year is 1860. so we have the final equation

  equation this is the first equation

Now by another condition we interchange the investment and get the annual interest as 1880

So we get the another equation as

9x+8y=188000

On simultaneously solving the equation we get

We multiply first equation by 9 and equation second by 8 and the subtract them

1674000 = 72x + 81y

1504000 = 72x + 64y

170000 = 17y

10000 = y

Now placing the values of y in equation first we get

186000 = 8x + 90000

96000 = 8x

12000 = x

Final Answer

The correct option is option B.Rs. 12000 in scheme A, Rs. 10000 in scheme B

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