Multiple choice

Zoya alone can complete an assignment in 30 days, and Yasmin alone can complete it in 40 days. If they work together on the assignment for 8 days, what fraction of the work is left?

  1. 5 14

  2. 9 13

  3. 8 15

  4. 7 11

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Combined rate is 1/30 + 1/40 = 7/120 per day. In 8 days they complete 8 x 7/120 = 56/120 = 7/15 of the work, leaving 1 - 7/15 = 8/15. The option '8 15' represents the fraction 8/15 with a missing slash.

AI explanation

Using the least common multiple method, let the total work be 120 units. Zoya's daily rate is 4 units and Yasmin's is 3 units, so their combined daily rate is 7 units. Working together for 8 days, they complete 56 units, leaving 64 units of work unfinished. The fraction of work left is 64 out of 120, which simplifies to 8/15.

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