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Three boys Alpha, Beta and Gama planned to make a sports car. Alpha and Beta can finish the task in 18 days; Beta and Gama can do it in 24 days while Gama and Alpha can finish it in 36 days. In how many days will each one of them finish it?1. Alpha = 48 days; Beta = 144/5 days; Gama = 144 days2. Alpha = 144 days; Beta = 144/5 days; Gama = 48 days3. Alpha = 144/5 days; Beta = 144 days; Gama = 48 days4. None of these |
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Answer» Correct Answer - Option 1 : Alpha = 48 days; Beta = 144/5 days; Gama = 144 days Given: Alpha and Beta can finish the task in 18 days; Beta and Gama can do it in 24 days while Gama and Alpha can finish it in 36 days. Calculation: Time taken by (Alpha + Beta) to finish the work = 18 days So, (Alpha + Beta)’s 1 day work = 1/18 ----(1) Time taken by (Beta + Gama) to finish the task = 24 days So, (Beta = Gama)’s 1 day work = 1/24 ----(2) Time taken by (Gama + Alpha) to finish the work = 36 days So, (Gama + Beta)’s 1 day work = 1/36 ----(3) On adding eq. (1), (2) and (3), we have 2(Alpha + Beta + Gama)’s 1 day work = 1/18 + 1/24 + 1/36 = (4 + 3 + 2)/72 = 9/72 = 1/8 Also, (Alpha + Beta + Gama)’s 1 day work = 1/(2 × 8) = 1/16 So, Alpha, Beta, Gama together can make a sports car in 16 days. Now, Alpha’s 1 day’s work = {(Alpha + Beta + Gama)’s 1 day’s work – (Beta + Gama)’s 1 day’s work} = 1/16 – 1/24 = (3 - 2)/48 = 1/48 Hence, Alpha alone can make the car in 48 days. Beta 1 day’s work = {(Alpha + Beta + Gama)’s 1 day’s work – (Gama + Alpha)’s 1 day’s work} = 1/16 – 1/36 = (9 - 4)/144 = 5/144 Hence, Beta alone can make the sports car in 144/5 days. Gama’s 1 day’s work = {(Alpha + Beta + Gama)’s 1 day’s work – (Alpha + Beta)’s 1 day’s work} = 1/16 – 1/18 = (9 - 8)/144 = 1/144 Hence, Gama alone can make the sports car in 144 days. ∴ Alpha, Beta and Gama alone can finish the task in 48 days, 144/5 days and 144 days respectively. |
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