Answer:
We should invest 9600 .
Explanation:
Interest received in Two and a half year = 1,200
So, Interest that should be received in a year = 1200×

= 480
Interest rate = 5%.
Let we had invested amount X.
Thus 5 % of X we will get in a year as interest
Which is
×X =
.
It is also equal to 480 as calculated above,
So. X = 480×20 = 9600.
Thus,
We should invest 9600 .