A can construct a wall in 40min and B can construct the wall in 45 min .how many hour needed to contruct a wall if both the person working together.

a 20 min
b 22 min
c 23 min
d 21 min

CTS noida (amcat 4-04-14)

• A's one minute work = 1/40
  
  B's one minute work = 1/45
  
  (A+B)'s one minute work = 1/40 + 1/45 = 85/40*45 = 17/360
  
  so, (A+B)will do work together in 360/17 min = 21 3/17 minutes
  
  d) 21 min
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• (1/40)+(1/45)=17/360
  
  360/17=approximately 21 min
• 10 years agoHelpfull: Yes(3) No(0)
• total work in one minut would be 1/40 + 1/45 = 17/360
  total time would be 360/17 == 21 approximate.
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• d
  by doing lcm this (1/40)+(1/45) and after reverse the answer
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• ans is 21min
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