Town PopulationDate: 05/03/97 at 05:04:26 From: Elicia Subject: Story Sums The population of town A is 4800 more than town B. If 3100 people move from town B to town A, the population in town A will be 11 times that of town B. Find the original, total population of the two towns. I did this: 10 units = 4800+3100+7900 1 unit = 7900/10 =790 790+3100 = 3890 Town B----3890 3890+4800 = 8690 Town A----8690 8690+3890 = 12580 The total population of the two towns at first is 12580, but my teacher said this is wrong. Date: 05/03/97 at 07:12:49 From: Doctor Anthony Subject: Re: Story Sums With this type of problem it is better to use symbols like x or y to represent unknown numbers. You can then write down equations, using these letters, to show what happens as you follow the instructions given in the question. Let x = initial population of town B x+4800 = initial population of town A Now move 3100 people from B to A: New population of B = x-3100 New population of A = x+4800+3100 Now the second of these is 11 times the first, so: x+4800+3100 = 11(x-3100) x+7900 = 11x-34100 7900+34100 = 10x 42000 = 10x x = 4200 Initial population of B was 4200 Initial population of A was 9000 The total for both towns = 4200 + 9000 = 13200 -Doctor Anthony, The Math Forum Check out our web site! http://mathforum.org/dr.math/ |
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