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The mean of the frequency table given below is 50. Then find out the values of a and b.classfrequency0-2020-4040-6060-8080-10017a32b19total120 |
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Answer»
mean = 50 \(\therefore\) \(\cfrac{3480+30a+70b}{120}\) = 50 30a + 70b = 6000 – 3480 30a + 70b = 2520 (1) 17 + 32 + 19 + a + b = 120 68 + a + b = 120, a + b = 52 (2) (2) x 30 => 30a + 30b = 1560 30a + 70b = 2520, 30a + 30b = 1560, 40b = 960, b = 960/40 = 24, a + 24 = 52 a = 52 – 24 = 28, \(\therefore\) a = 28, b = 24 |
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