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Two men a and b, can do a piece of work in 9 hours and 18 hours respectively. If A,B and C working together can finish it in 5 hours,in how many hors will C alone do the same work? |
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Answer» work done by a in 9 hours = 9 work done by a in 1 hour= 1/9 hours work done by B in 18 hours= 18 work done by b in 1 hour = 1/18 hours work done by a,b and c = 5 hours work done by a, b and c in 1 hour= 1/5 so now to find the value of c we must SUBTRACT the total work done by and b in 1 hour by a,b and c in 1 hour (a+b+c) - ( a+b) 1/5-{1/9+1/18} 1/5-{2+1/18). LCM = 18 1/5-3/18 18-15/90. LCM= 90 3/90 1/30 . . . work done by c in 1 hour is 1/30 so work done by c = 30 hours |
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