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?
Choices:
A) 180 bricks B) 190 bricks C) 170 bricks D) 160 bricks E) 195 bricks
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.   ANSWER:190 bricks
<result>B</result>
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?