Answers

2014-07-22T20:15:05+08:00
Painter 1 can paint a room in 12 hrs
so in 1 hrs he can paint 1/12 part of a room
painter 2 can paint a room in 10 hrs
so in 1 hrs he can paint 1/10 part of a room
together in1 hrs they can paint       (1/12 + 1/10)     part of a
room    =        ( 5 + 6)/60  =  11/60        >     LCM = 60
thus  no. of hrs to complete the room  =    60/11  ~  5.45hrs
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