X is 60% more efficient than Y. They work together and complete a certain job. If X can complete the same job alone in 23 days, then on which day from the start of the work will they finish the job, working together?

Because X is 60% more efficient than Y, the ratio of their efficiencies is 5 to 3. Using the inverse efficiency rule, if X takes 23 days alone, Y takes 23 multiplied by 5/3 days. The combined daily work of X and Y is 1/23 plus 3/115, which equals 8/115 of the job per day. Working together, they finish the total work in 115/8 days, meaning the job is completed on the 15th day.

• Thanks
• Wrong explanation