Answer: 55.4 mins
Step-by-step explanation:
pragnesh and qazi = 2hrs
pragnesh and roghui = 3hrs
qazi and roghui = 4hrs
this means for every 1 hour they wold paint.
pragnesh and qazi = half of the fence
pragnesh and roghui =
qazi and roghui = quarter of the fence
time taken when they all work together
= +
+
=
=
= 0.9231 × 60(mins)
= 55.4 mins