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A work is assigned to total of 150 workers for a fixed days. 8 more days are required tocomplete that work if four workers are fail to work day by day constantly from the startingday, then after how many days the work finishes?OR |
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Answer» Let, 150 men would have completed the work in 'n' days working all days. Now no. of men & no. of days are inversely proportional. So, we get, 150n = constant ----------->(1) But, from 2nd day, 4 men left and so on and it took 8 days more than the normal to finish the work, ie, (n + 8) days. Consequently, 150 + 146 + 142 +.......to (n+8) terms = constant Left hand side is an A.P, with 1st term =150, common difference = -4 So, using formula, (n+8)*1/2*[2*150+(n+8-1)(-4)]= constant ------->(2) From equations, (n+8)[300+(n+7)(-4)]=300n Solving the quadratic equation, we get, n = 17, or -32(neglected) Hence, work is completed in, n+8 = 17 + 8 = 25 days |
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