A man invests a certain sum of money at 6% per annum simple interest and another at 7% per annum simple interest. His income from interest after 2 yr was ₹ 792. Also, half of the first sum is equal to one-third of the second sum. The total sum invested was?
Correct Answer: ₹ 6000
Explanation:
Let the sum be P and Q, respectively.
Then, (P x 6 x 2)/100 + (Q x 7 x 2)/100 = 792
⇒ 6P + 7Q = 39600 ...(i) Also P/2 = Q/3 ⇒ 3P = 2Q ... (ii) On solving Eqs . (i) and (ii), we get P = 2400 and Q = 3600
∴ Total sum = (2400 + 3600) = ₹ 6000
