Multiple choice

A completes $3/4$ of a work in $18$ days, B $2/3$ of the work in $12$ days and C. $60$% of the same work in $24$ days. A, B and C separately work for $4, 6$ and $8$ days respectively, then how much percent the work is still pending?

  1. $40$%
  2. $25$%
  3. $30$%
  4. $27$%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A's rate = (3/4)/18 = 1/24 per day. B's rate = (2/3)/12 = 1/18 per day. C's rate = 0.6/24 = 1/40 per day. Work done = 4*(1/24) + 6*(1/18) + 8*(1/40) = 1/6 + 1/3 + 1/5 = (5+10+6)/30 = 21/30 = 0.7. Pending work = 1 - 0.7 = 0.3 or 30%.

AI explanation

The daily work rate for A is (3/4) divided by 18, which equals 1/24 of the work per day. The daily work rates for B and C are (2/3) divided by 12 and 0.60 divided by 24, simplifying to 1/18 and 1/40 respectively. Working for 4, 6, and 8 days, they complete 4/24, 6/18, and 8/40 of the work, which is 1/6, 1/3, and 1/5 respectively. Adding these completed portions gives a total of 7/10 of the work finished. Therefore, the pending work is 1 minus 7/10, which is 3/10, equaling 30 percent.

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