Answer:
first account with 6% interest ( x ) = $46000
second account with 4% interest ( y ) = $19000
Step-by-step explanation:
Principal = $65000
first interest rate = 6%
second interest rate = 4% 
assuming ; X = money invested in first account ,  Y = money invested in second account 
hence :
 ( 65000 - y ) * 6% + ( 65000 - x ) * 4% = 3520 
 3900 - 0.06 y  + 2600 - 0.04 x = 3520 
0.04 x + 0.06 y = 3900 + 2600 - 3520 
0.04 x + 0.06 y = 2980 ----- ( 1) 
         x + y = 65000  ------- ( 2 ) 
solve equation 1 and 2 simultaneously by elimination method 
0.04 x + 0.06 y = 2980 ------  ( 3 )
0.06 x + 0.06 y = 3900 ------- ( 4 ) 
subtract equation 3 form equation 4 
0.02 x  = 920 ,   hence x = $46000
therefore y = $65000 - $46000 =  $19000