Answer
$r = 6$%
$Y=9000$
Work Step by Step
$0.06Y - 5000r = 240$
$0.06Y + 6000r = 900$
Multiply first equation by -1 and add to second equation to eliminate Y
$-0.06Y + 5000r = -240$
$0.06Y + 6000r = 900$
$5000r + 6000r = -240 + 900$
$11000r = 660$
$r=0.06$
$0.06Y - 5000 \times 0.06 = 240$
$0.06Y - 300 = 240$
$0.06Y = 240 + 300$
$0.06Y = 540$
$Y=9000$
Plug the Y in one of the equations and evaluate r
$r=0.06$
