Multiple choice

A does a work in $10$ days and B does the same work in $15$ days. In how many days they together will do the same work.

  1. $6$ days
  2. $5$ days
  3. $9$ days
  4. $8$ days
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

If A takes 10 days and B takes 15 days, their combined rate is 1/10 + 1/15 = 3/30 + 2/30 = 5/30 = 1/6. Thus, they take 6 days to complete the work together.

AI explanation

Taking the least common multiple of 10 and 15 as the total work gives 30 units, meaning A completes 3 units and B completes 2 units per day. Their combined daily capacity is $3 + 2 = 5$ units, so dividing the total work of 30 units by 5 units per day yields a completion time of 6 days.

Keep practicing — related questions