Let x be the amount she puts on the account paying 4% and y be the amount at the 10%.
x = 2y
0.04x + 0.1y = 7254
Now let's solve the system. Let's subtitute the first equation into the second:
0.04(2y) +0.1y= 7254
0.18y = 7254
y= 40,300
x= 2y
x = 80,600
She invested 80,600 at 4% and 40,300 at 10%.