Let
x = number of rs 50
y = number of rs 20
z = number of rs 10
Because there are 25 total notes,
x + y +  z = 25              (1)
The ratio of rs 50 to rs 20 is 3:5, therefore
x = 0.6y                       (2)
The total amount is rs 590, therefore
50x + 20y + 10z = 590      
or
5x + 2y + z = 59            (3)
Subtract (1) from (3).
4x + y = 34            (4)
Substitute (2) into (4).
4*(0.6y) + y = 34
3.4y = 34
y = 10
From (2), obtain
x = 6
From (1), obtain
z = 25 - 6 - 10 = 9
Answer:
Kaveri has 
 6 rs 50 notes, 
10 rs 20 notes,
 9 rs 10 notes.