If 6 men and 8 boys can do a piece of work in 10 days while 26 men and 48 boys can do the same in 2 days, the time taken by 15 men and 20 boys in doing the same type of work will be: MCQ with Answer and Explanation
If 6 men and 8 boys can do a piece of work in 10 days while 26 men and 48 boys can do the same in 2 days, the time taken by 15 men and 20 boys in doing the same type of work will be:
A. 6 days
B. 4 days
C. 7 days
D. 5 days
Answer: Option B
Solution (By JKSSB Mock Tests)
Total work = 10 * (6M + 8B) = 2 * (26M + 48B) => 60M + 80B = 52M + 96B => 8M = 16B => 1M = 2B. Total work in terms of boys = 10 * (6*2B + 8B) = 10 * 20B = 200 boy-days. Efficiency of 15 men and 20 boys = 15*2B + 20B = 50B. Time taken = 200 / 50 = 4 days.
A, B and C can do a piece of work in 24, 30 and 40 days respectively. They began the work together but C left 4 days before the completion of the work. In how many days was the work completed?
Explanation:
Total work = LCM(24, 30, 40) = 120 units. Efficiencies: A = 5, B = 4, C = 3. Total efficiency = 12 units/day. Since C left 4 days before completion, add the work C would have done in those 4 days: 120 + (3 * 4) = 132 units. Total days = 132 / 12 = 11 days.
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