UPSC CSE Prelims 2023
Consider the following statements:
Which. of the above statements is/are correct?
To determine the total work, the Least Common Multiple (LCM) of the individual days taken by A, B, and C is calculated. The LCM of 8, 16, and 12 is 48 units. This represents the total work.
The efficiency of each person per day is:
The work pattern is A on Monday, B on Tuesday, and C on Wednesday, repeating in cycles. Therefore, in one 3-day cycle (Monday, Tuesday, Wednesday), the total work completed is:
To find how many such cycles are needed for 48 units of work:
After 9 days, 39 units of work are completed. The 10th day will be a Monday (start of a new cycle), and A will work:
The 11th day will be a Tuesday, and B will work:
Thus, the work is finished on the 11th day. To determine the day of the week for the 11th day, considering Day 1 is Monday:
Therefore, the work is finished on Thursday. Statement 1 is correct. The work is finished in 11 days, not 10 days, making Statement 2 incorrect.
Options 2, 3, and 4 are incorrect because the detailed calculation demonstrates that the work is completed on the 11th day, which corresponds to a Thursday. This confirms that only statement 1 is accurate, while statement 2, asserting completion in 10 days, is false.