SOLUTION: Translate the problem into a pair of linear equations in two variables. Solve the equations using either elimination or substitution. State your answer for the specified variable.

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Question 282214: Translate the problem into a pair of linear equations in two variables. Solve the equations using either elimination or substitution. State your answer for the specified variable.
Mardi received an inheritance of $70,000. She invested part at 10% and deposited the remainder in tax-free bonds at 8%. Her total annual income from the investments was $6800. Find the amount invested at 10%.
Answer by mananth(16946) (Show Source):
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Mardi received an inheritance of $70,000. She invested part at 10% and deposited the remainder in tax-free bonds at 8%. Her total annual income from the investments was $6800. Find the amount invested at 10%.
Let Mardi invest $ x at 10%
And $y at 8%
x+y=70000 ---------------1
The sum of interest from each investment = 6800
0.1x+0.08y=6800----------2
Multiply equation 2 by 10
x+0.8y=68000 .----------3
x+0.8y -(x+y)= 68000-70000
x+0.8y-x-y= -2000
-0.2y=-2000
y= 2000/-0.2
y=10000
If y =10000
then x= 60000 investment in 10% bonds