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 ₹ 1860 as annual interest. However, had she interchanged the amount of investments in the two schemes, she would have received ₹ 20 more as annual interest. How much money did she invest in each scheme?

Question

Philoid · Accepted Answer

Let the amount of investments in schemes A and B ₹ x and ₹ y, respectively.

Case I Interest at the rate of 8% per annum on scheme A + Interest at the rate of 9% per annum on scheme B = Total amount received

₹

Since,

so, 8x + 9y = 186000 …(i)

Case II Interest at the rate of 9% per annum on scheme A + Interest at the rate of 8% per annum on scheme B = ₹ 20 more as annual Interest

So, 9x + 8y = 188000 …(ii)

On multiplying Eq. (i) by 9 and Eq. (ii) by 8 and then subtracting them, we get

(72x + 81y) – (72x + 64y) = 186000 – 188000

17y = 170000

y = 10000

On putting the value of y in Eq. (i), we get

8x + 9(10000) = 186000

So x = 12000

Hence, she invested ₹ 12000 and ₹ 10000 in two schemes A and B, respectively.