grandh01 wrote:A total of $20,000 was invested in two
certificates of deposit at simple annual
interest rates of 6 percent and 8 percent,
respectively. If the total interest on the
two certificates was $1,440 at the
end of one year, what fractional part
of the $20.000 was invested at the
higher rate?
(A)3/8
(B)2/5
(C)1/2
(D)3/5
(E)3/4

Amount invested at 6% = x---------- Interest after 1year = 6% * x
Amount invested at 8% = 20,000-x--- Interest after 1year = 8% * (20,000-x)

Total interest after 1year = 0.06x + 1600 - 0.08x = 1600 - 0.02x = 1440; x = 8000

Amount invested at higher rate = 20,000-x = 12,000
Fraction of total amount = 12,000 / 20,000 = 3/5
Ans = d