Question 511519
You have to keep the counts of the items separate from their values.
.
a = number of acoustic guitars
339a = value of the acoustic guitars
.
e = number of electric guitars
479e = value of electric guitars
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a + e = 9 guitars sold
so
a = 9-e
.
339a + 479e = 3611
.
substitute a=9-e
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339(9-e) + 479e = 3611
.
3051 -339e +479e = 3611
.
140e = 3611-3051
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140e = 560
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e = 4
.
a = 9-e
.
a = 9-4
.
a = 5
.
Check the values to be sure this is the right answer.
339*5 + 479*4 = ??
339*5 + 479*4 = 3611
Correct.
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Answer: They sold 4 electric guitars and 5 acoustic guitars.
.
Done.