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?
Options:  A) 45  B) B.60  C) C.80  D) D.90  E) be determined
A and B together can complete one-ninth of a job in a day means that AB 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 10 days 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= 
<gadget id="calculator">90 - 10</gadget>
<output>80</output>
80 Days   Option C.80
<result>C</result>
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?