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- A and B together can complete a task in 20 days.
Question 1:
A and B together can complete a task in 20 days. B and C together can complete the same task in 30 days. A and C together can complete the same task in 30 days. What is the respective ratio of the number of days taken by A when completing the same task alone to the number of days taken by C when completing the same task alone? A. 1:3
Feedback Efficiency of A and B = 1/20 per day = 5% per day ________________1
Efficiency of B and C = 1/30 per day = 3.33% per day______________2
Efficiency of C and A = 1/30 per day = 3.33% per day______________3
Taking equation 2 and 3 together
B + C = 3.33% and C + A = 3.33%
C and 3.33% will be removed. Hence A = B
Efficiency of A = B = 5%/2 = 2.5% = 1/40
Efficiency of C = 3.33% - 2.5% = 0.833% = 1/120
A can do the job in 40 days and C can do the job in 120 days if they work alone.
Ratio of number of days in which A and C can complete the job 1:3.
Efficiency of B and C = 1/30 per day = 3.33% per day______________2
Efficiency of C and A = 1/30 per day = 3.33% per day______________3
Taking equation 2 and 3 together
B + C = 3.33% and C + A = 3.33%
C and 3.33% will be removed. Hence A = B
Efficiency of A = B = 5%/2 = 2.5% = 1/40
Efficiency of C = 3.33% - 2.5% = 0.833% = 1/120
A can do the job in 40 days and C can do the job in 120 days if they work alone.
Ratio of number of days in which A and C can complete the job 1:3.
B. 2:4
C. 3:1
D. 4:5
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