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Brazen can paint a wall red in 12 days, while Ballary can paint the entire wall in 21 days. If Brazen and Ballari work alternately for one day each from painting the wall to coloring it red, then how many hours will it take to paint the entire wall red?1. 16 days2. 15 days3. 14 days4. 12 days |
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Answer» Correct Answer - Option 2 : 15 days Given: Brazen can paint a wall in 12 days Ballary can paint the wall in 21 days Formula used: If a person can complete the work in A days, then the person can complete 1/A work in 1 day. Calculation: Work completed by Brazen in 1 day = 1/12 Work completed by Ballary in 1 day = 1/21 Total work completed by them in 1 day = 1/12 + 1/21 ⇒ Total work completed by them in 2 days = (7 + 4)/84 ⇒ Total work completed by them in 2 days = 11/84 Total work completed by them in 7 × 2 days = 14 days = 77/84 ⇒ Remaining work = 1 – 77/84 = 7/84 = 1/12 Brazen can do 1/12 work in 1 day Total time taken = 14 + 1 = 15 days ∴ Total time taken is 15 days |
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