A make a wall in 9 hour. B makes a wall in 10 hour. When doing together 10 more bricks are required and together make a wall in 5 hour. How many bricks r there in the wall?

• 190 bricks are there in the wall.
  Time taken by Aand B together to complete same brick job = 1/(1/9 +1/10) = 90/19 hrs.
  
  Actual time taken = 5 hrs
  
  extra time taken for 10 bricks job = 5-90/19 = 5/19 hrs
  
  so 5/19 hrs are reqd for 10 bricks
  5 hrs are reqd for 190 bricks.
  
  so initially 180 bricks were reqd.
  Finally 190 bricks are used.
• 12 years agoHelpfull: Yes(20) No(2)