Multiple choice

Atul can complete an assignment in 12 days, Harman in 8 days and Chetan in 10 days. Harman and Chetan started the assignment, but were asked to stop after 3 days. In how many days would Atul complete the assignment now?

  1. 3.9 days

  2. 4 days

  3. 4.5 days

  4. 7.3 days

  5. 8.2 days
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Harman and Chetan's combined rate is 1/8 + 1/10 = 5/40 + 4/40 = 9/40 per day. In 3 days, they complete 3 * 9/40 = 27/40 of the work. Remaining work = 1 - 27/40 = 13/40. Atul's rate is 1/12. Time for Atul = (13/40) / (1/12) = (13 * 12) / 40 = 156 / 40 = 3.9 days.

AI explanation

Let the total assignment be the least common multiple of 12, 8, and 10, which is 120 units. The daily work of Atul is 10 units, Harman is 15 units, and Chetan is 12 units. Harman and Chetan work together for 3 days, completing 3 x (15 + 12) = 81 units. The remaining work is 120 minus 81 = 39 units. Atul completes this remaining work in 39 divided by 10 days, which equals 3.9 days.

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