WEBVTT
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Two babies were born on the same day.
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One of them weighed three kilograms and the other 3.6 kilograms.
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Per week, the first baby gained 190 grams and the other gained 140 grams.
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At what age in weeks will they weigh the same?
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When the first baby was born, it weighed three kilograms.
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This is equal to 3000 grams, as there are 1000 grams in one kilogram.
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This baby increased in weight by 190 grams per week.
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The second baby weighed 3.6 kilograms when born.
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This is equal to 3600 grams.
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The second baby increased in weight by 140 grams per week.
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If we let 𝑥 be the number of weeks when the weights of the two babies are equal, we can set up a linear equation.
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The weight of baby one is given by the expression 3000 plus 190𝑥.
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And the weight of baby two is given by the expression 3600 plus 140𝑥.
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We want to calculate 𝑥 when these two expressions are equal.
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Subtracting 140𝑥 from both sides of the equation gives us 3000 plus 50𝑥 is equal to 3600.
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Subtracting 3000 from both sides of this new equation gives us 50𝑥 is equal to 600, as 3600 minus 3000 is equal to 600.
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Finally, dividing both sides by 50 gives us a value for 𝑥 equal to 12.
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We can therefore say that the two babies will weigh the same after 12 weeks.
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After 12 weeks, both babies will weigh 5280 grams.