Question 165151
Let the amounts in three different accounts be x,y,z respectively.
Then x + y + z = 25000 ------------(1)
and annual interest of x is 8%
y is 6%
z is 4%
The amount deposited in the 8% account is twice the amount in the 6% account. 
That is x=2y --------------------(2)
the three accounts earns total annual interest of $1520
that gives 8%x + 6%y + 4%z = 1520
8x + 6y + 4z = 152000
4x + 3y + 2z = 76000 --------------(3)
Solving the 3 eqns for x,y,z
plug x=2y in eqns 1 and 3
3y + z = 25000 ----------(4)
11y + 2z = 76000 ----------(5)
subtract eqns (5) and 2* eqn (4)
5y = 26000
y = 5200
x = 10400 from eqn (2)
and z = 9400 from eqn (1)

The money deposited in the 3 accounts is 10400, 5200 and 9400