Question 257358
This is a I=PRT problem. IN this case we have 2 rates,so we get
(i) {{{I = prt + prt}}}
From above, (i) becomes
(ii) {{{890 = x(.07)(1) + (12000-x)(.09)(1)}}}
which is
{{{890 = .07x + 1080 -.09x}}}
{{{890 = -.02x + 1080}}}
{{{.02x = 190}}}
x = 9500
12000-x = 2500
So it appears we have 
9500 @ 7%
2500 @ 9%