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 = [tex]\frac{1}{2}[/tex] half of the fence
pragnesh and roghui = [tex]\frac{1}{3}[/tex]
qazi and roghui = [tex]\frac{1}{4}[/tex] quarter of the fence
time taken when they all work together
= [tex]\frac{1}{2}[/tex] + [tex]\frac{1}{3}[/tex] + [tex]\frac{1}{4}[/tex]
= [tex]\frac{13}{12}[/tex]
= [tex]\frac{12}{13}[/tex]
= 0.9231 × 60(mins)
= 55.4 mins