Question

The population of a town is 8000.If males are increased by 6% and females are increased by 10%, the population will be 8600. FInd the number of females in the town ?

Answer 1

Let males x
Then, females 8000-x
x*.06+(8000-x)*.1=8600-8000
800-600=.04x
x=200/.04
  =5000

So, females=3000

Answer 2

x - the number of males,
y - the number of females;
x + y = 8,000
1.06 x + 1.10 y = 8,600 / * 100
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106 x + 110 y = 860,000
x + y = 8,000    / * (-106 )
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106 x + 110 y = 860,000
+
-106 x - 106 y = - 848,000
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                 4 y = 12,000
                  y  = 12,000 : 4
                  y = 3,000
Answer: The number of females in town is 3,000.