#$6000# are partly invested at #5%# and partly at at #9%#. If interest earned in a year is #$400#, what are amounts invested at #5%# and at #9%#?

1 Answer
Apr 14, 2017

Answer:

Amount invested at #5%# is #$3,500# and amount invested at #9%# is #$2,500#

Explanation:

Let the amount invested at #5%# be #x#, then amount invested at #9%# will be #6000-x#.

Therefore, interest earned on #5%# is #(5x)/100# and interest earned on #9%# is #(6000-x)9/100#. As total interest is #$400#, we have

#(5x)/100+9/100(6000-x)=400#

or #5x+9(6000-x)=40000#

or #5x+54000-9x=40000#

or #-4x=-14000#

#x=(-14000)/(-4)=3500#

Hence amount invested at #5%# is #$3,500# and amount invested at #9%# is #6000-3500=$2,500#