Question

Bhagwanti inherited Rs 12000.00. She invested part of it as 10% and the rest at 12%. Her annual income from these investments is Rs 1280.00. How much did she invest at each rate?

Answer 1

At the rate of 10 % , let the investment by Bhagwanti be Rs . x . 
Therefore, at the rate of 12 % , the investment will be Rs . (12000 - x) . 
At the rate of 10 % , her annual income = \[x \times 10 % \]
At the rate of 12 % , her annual income =\[ (12000 - x) \times \]12 % 
So, 
\[x \times 0 . 1 + 0 . 12(12000 - x) = 1280\]
or 0 . 1x - 0 . 12x = 1280 - 1440
or 0 . 02x = 160
or x = 8000
Thus, at the rate of 10 % , she invested Rs . 8000 and at the rate of 12 % , she invested Rs . 4000 (12000 - 8000).