SravnaTestPrep wrote:
A and B together can complete one-ninth of a job in a day. What is the difference between the maximum and minimum number of days A could take to complete the job alone, if A and B take whole number of days to complete the job alone?
A 45
B.60
C.80
D.90
E.Cannot be determined
Given, A & B together can complete 1/9th of the job in one day.
Let the job consist of 90 units. Therefore in one day A & B together can produce 10 units.
A & B together work at a rate of 10 units/day
So the combinations for the no. of units per day produced by A & B can be (1,9), (2,8), (3,7), (4,6), (5,5), (6,4), (7,3), (8,2), (9,1)
So Maximum units produced per day by A = 9 units/ day at its highest efficiency.
Hence to complete 90 units, A will take (90/9) = 10 days, this is the fastest for A at its highest efficiency.
So Minimum Days to finish the job = 10 days
Now, Similarly, minimum units produced per day by A = 1 unit/ day at its lowest efficiency.
Hence to complete 90 units, A will take (90/1) = 90 days, this is the slowest for a its lowest efficiency.
So Maximum Days to finish the job = 90 days
Required is Difference of Max Days & Min Days = 90 - 10 = 80
Answer C
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