Question 60022
Let the amount invested in federal notes be x$
Then amount invested in bonds = (30,000 - x)$

Yield from the federal notes = 0.09x
Yield from the bonds = (30,000-x)(0.08)

From the data given,
0.09x + (30,000-x)(0.08) = 2500
==> 0.09x + 30,000*0.08 - 0.08x = 2500
==> 0.09x + 2400 - 0.08x = 2500
==> 0.01x + 2400 = 2500
==> 0.01x +2400 - 2400 = 2500 - 2400
==> 0.01x = 100
==> 0.01x/0.01 = 100/0.01
==> x = 10,000

==> the amount invested in federal notes = $10,000
and the amount invested in bonds = 30,000-10,000
                                 = 20,000$


Good Luck!!!