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:

Let the investment in 9% stock be Rs. x.

Then, investment in 10% stock = Rs. (9800 - x).

	3x	=	9800 - x
	25		8

 24x = 9800 x 25 - 25x

 49x = 9800 x 25

 x = 5000.