Bite-sized brain teaser to solve in a minute or less.
The Fence‑Painting Timer
Category: Work‑Rate, Math Puzzle
Painter A can paint a fence in 4 hours. Painter B can paint the same fence in 6 hours. Working side by side, how long will it take them to finish painting the fence together?
Solution
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Painter A’s rate: 1 fence ÷ 4 hour = ¼ fence / hour Painter B’s rate: 1 fence ÷ 6 hour = ¹⁄₆ fence / hour Combined rate: ¼ + ¹⁄₆ = (3/12 + 2/12) = 5/12 fence / hour Time to paint the fence together: 1 ÷ (5/12) = 12/5 = 2.4 hours = 2 hours 24 minutes Answer: Painters A and B can paint the fence together in 2 hours 24 minutes |
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