SOLUTION: select the set of equations that represent the following situation. Mary invested one amount at 10% simple interest, and a second amount at 3% interest, earning $21.72 in one year.
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-> SOLUTION: select the set of equations that represent the following situation. Mary invested one amount at 10% simple interest, and a second amount at 3% interest, earning $21.72 in one year.
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Question 624391: select the set of equations that represent the following situation. Mary invested one amount at 10% simple interest, and a second amount at 3% interest, earning $21.72 in one year. If she had switched the amounts, she would have earned $15.07. What were the two amounts. Answer by josmiceli(19441) (Show Source):
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(1)
(2)
Multiply both sides of (1) by
and both sides of (2) by
(1)
(2)
Subtract (1) from (2)
(2)
(1)
Plug this result back into either equation
(2)
(2)
(2)
(2)
(2)
$189 was invested @ 10%
$94 was invested @ 3%
check:
OK
