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

A and B together can complete one-ninth of a job in a day means that A & B together does one whole work in 9 days.

1/A +1/B = 1/9

The minimum value A can take is 10 days (Anything less than 10days is not possible because in other case, no of days taken by B will become negative, which is not possible practically)

When A takes least time (10Days) then B would take the Max time (90 days) to complete the work alone. In order to find the Max time taken by A, find out the min time taken by B as we did earlier.

The minimum value B can take is 10 days (Anything less than 10days is not possible because in other case, no of days taken by A will become negative, which is not possible practically)

When B takes least time (10Days) then A would take the Max time (90 days) to complete the work alone. So the required difference = Max Time taken-Min Time taken

= 90 - 10

=80 Days

Option C

Good conceptual question.

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