Work done by A, B, and C in 1 day = 1/30 + 1/24 + 1/20 = 4/120 + 5/120 + 6/120 = 15/120 = 1/8 of the project per day. Work completed by all in 5 days = 5 × 1/8 = 5/8 of the project. Remaining work = 1 - 5/8 = 3/8 of the project. Work done by B and C together in 1 day = 1/24 + 1/20 = 5/120 + 6/120 = 11/120 of the project per day. Time taken by B and C to finish the remaining 3/8 work = (3/8) ÷ (11/120) = 3/8 × 120/11 = 45/11 = 4.09 days.= 4 days(approx)
An examinee is required to answer 7 questions out of 14 questions, which are divided into two groups each containing 7 questions. He is not permitted to...
In how many ways can the letters of the word VOWEL can be arranged so that all the consonants occupy odd places, vowels come on even places?
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In how ways can the selection be made so that a particular member is always excluded?
