Practicia completes the job in one hour = 1/4
Naoimi completes the job in one hour = 1/5
If Parcticia and Naoimi does it together,let us suppose in x number of hours.
The equation so form is:
(1/4)*x + (1/6)*x = 1 (i.e job finished)
The Least common multiple(LCM) of 4 and 6 = 12
12*(1/4)*x + 12*(1/6)*x = 12*1
Therefore, solving the equation we get,
3x + 2x = 12
5x = 12
x = 12/5
x= 2 2/5 hours or 2.24 hours
Therefore number of hours they took to complete the work is 2 hours and 24 minutes or 2.24 hours.