From the statement, we can understand that Kartik reads an average of 50 pages per day. This is the total number of pages he reads divided by the total number of days, which comes out to be 50 pages daily.
The question then tells us that Kartik reads 50 pages per day during the week. The week comprises weekdays (Monday to Friday). This provides more information about his reading habit, specifically about his reading on weekdays.
Now, the statement wants to know when Kartik reads 1.5 times as much than usual. If Kartik reads 50 pages per day on weekdays and his average reading is also 50 pages per day, this means that there is no day in which he reads 1.5 times of his average. Because his daily average reading is the same as his reading on weekdays.
From the options provided, the most feasible answer would be 4) weekdays. This is because Kartik reads the same number of pages, i.e., 50 pages on average daily and also on weekdays. So, comparing his reading on weekdays with the average, he reads 1 times (not 1.5 times) more on weekdays.
This evidence leads us to the conclusion: There is no specific day on which Kartik reads 1.5 times his average because he reads the same amount each day of the week, and his daily average indicates that.
Therefore, the answer to the question is 4) weekdays, knowing that Kartik reads the same amount on weekdays as his average.
Answer: 4) weekdays