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the mean weight of 120 students of b.com class is 60 kgs the mean weight of boys is 55 kgs and that of girls is 45 kgs find the number of boys and girls |
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Answer» Answer: Let the number of boys be B and the number of girls, G. Let us FORM the equation from the given statements. B + G = 150 … (1). The TOTAL weight of boys and girls is 70B + 55G = 150*60 = 9000 … (2) The HCF in (2) is 5, so dividing right through by 5 we get 14B + 11G = 1800 … (3) Multiply (1) by 11 to get 11B + 11G = 150*11 = 1650 … (4). Subtract (4) from (3) to get 14B + 11G -11B - 11G= 1800 - 1650, or 3B = 150. or B = 50, then G = 150 - 50 = 100. Check: Total weight of B and G = 50*70 + 100*55 = 3500+5500 = 9000. Answer: Boys = 50, Girls = 100. |
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