A can paint a wall in 3 hours, with the help of B they can fill in 2 hours. In how much time B alone will paint the wall:
Correct answer: A. 6
- A. 6
- B. 3
- C. 2
- D. 5
Explanation
To solve this, first determine the work rate of A. A can paint a wall in 3 hours, so A's rate is 1/3 of a wall per hour. Together, A and B can paint a wall in 2 hours, so their combined rate is 1/2 of a wall per hour. Let B's rate be 1/b. Thus, the equation is:1/3 + 1/b = 1/2.Solving for 1/b gives:1/b = 1/2 - 1/3 = 1/6.So, b = 6 hours, meaning B alone takes 6 hours to paint the wall.Options B, C, and D are incorrect because they do not match the calculated time B takes alone.
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