Multiple choice

Jacob, Jack, Summer and Amina are doing same work. Jack takes 4 days more than Jacob. The efficiency of Jack is double that of Summer. The ratio of efficiencies of Summer and Amina is 1 : 4. Amina takes 8 days to complete the work. A. Jacob takes 12 days to complete the work. B. The difference between the number of days taken by Jack and by Summer to complete the work alone is 20. C. Jack takes the least number of days to complete the work. D. Jacob and Jack will take 8 days to complete the work together. Which of the above statements is/are correct?

  1. (A), (B) and (D)

  2. (A) and (C) only

  3. (A) and (B) only

  4. (A) only

  5. NA
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Amina takes 8 days. Efficiency ratio Summer:Amina = 1:4. Summer takes 4 times longer = 32 days. Efficiency Jack = 2 * Summer = 2 * (1/32) = 1/16. Jack takes 16 days. Jack takes 4 days more than Jacob, so Jacob takes 12 days. (A) Jacob takes 12 days is correct. (B) Jack (16) - Summer (32) = 16, not 20. (C) Jack (16) vs Jacob (12), Jacob is faster. (D) 1/12 + 1/16 = 7/48. Time = 48/7 = 6.85 days.

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