math
posted by Sam on .
Formulate but do not solve the problem.
Michael Perez has a total of $1802 on deposit with two savings institutions. One (x) pays interest at a rate of 6% per year, whereas the other (y) pays interest at a rate of 8% per year. If Michael earned a total of $117 in interest during a single year, how much does he have on deposit in each institution?
= 117
= 1802

$X in acc. 1.
$Y in acc. 2.
Eq1: 0.06X + 0.08Y = 117.
Eq2: X + Y = 1802.
Multiply Eq1 by 100 and Eq2 by 6 and get:
6X + 8Y = 11700
6X  6Y = 10812
Add the Eqs:
2Y = 888
Y = $444 in acc. 2.
X + 444 = 1802
X = 1802  444 = $1358 in acc. 1.