Rs. 9800 are invested partly in 9% stock at 75 and 10% stock at 80 to have equal amount of incomes. The investment in 9% stock is___________?

A. Rs. 4800
B. Rs. 5400
C. Rs. 5000
D. Rs. 5600
Let the investment in 9% stock is x.
investment in 10% stock = (9800 – x)
9/75 * x = 10/80(9800 – x) hence x = 5000