Working alone it takes mark 7 hours to mop the whole house it takes sue 9 determine to the nearest hundredth of the hour how long it will take then to mop the house together

3.9375 hours

Step-by-step explanation:

Working alone it takes mark 7 hours to mop the whole house it takes sue 9 determine to the nearest hundredth of the hour how long it will take then to mop the house together

This is calculated as

1/Time it would take them to work together = 1/ Number of hours Mark mopped + 1/ Number of hours Sue mopped

= 1/T = 1/7 + 1/9

Lowest common denominator = 63

1/T = 9 + 7/63

1/T = 16/63

T = 63/16

T = 3.9375 hours

step-by-step explanation:

this is not possible to solve with the info given.   you need at least an one angle somewhere.