The birthday of Mishti falls on Thursday 27 April of a certain year. In the same year, on which day of the week will the birthday of Aradhya fall if she was born on 20 October?

Introduction / Context:
This problem again compares two birthdays within the same year, this time moving from late April to late October. You know the weekday for 27 April and must find the weekday for 20 October. This involves counting across several months and then converting the total number of days into a weekday shift.

Given Data / Assumptions:

• Mishti has a birthday on Thursday 27 April.
• Aradhya has a birthday on 20 October of the same year.
• Month lengths: April 30, May 31, June 30, July 31, August 31, September 30, October 31.
• The year is assumed to be a normal year.

Concept / Approach:
To find the weekday difference, we count the days from 27 April up to 20 October, convert that into odd days by dividing by 7, and then shift the weekday of 27 April by that many odd days. Keeping the calculation structured month by month reduces the chance of errors.

Step-by-Step Solution:
Step 1: Days remaining in April after 27 April are 30 - 27 = 3 days. Step 2: Full months between May and September: May 31, June 30, July 31, August 31, September 30. Step 3: Sum these full months: 31 + 30 + 31 + 31 + 30 = 153 days. Step 4: Days in October up to 20 October inclusive are 20 days. Step 5: Total days from 27 April to 20 October = 3 + 153 + 20 = 176 days. Step 6: Compute odd days: 176 divided by 7 gives remainder 1 because 176 = 7 * 25 + 1. Therefore, the weekday moves forward by one day from Thursday to Friday.

Verification / Alternative check:
You can check the logic by going in smaller jumps. For example, from 27 April to 27 May is 30 days giving 2 odd days, from 27 May to 27 June adds another month, and so on. Carefully tracking the weekday step by step again leads to a one day net shift when you reach 20 October, confirming that the weekday is Friday.

Why Other Options Are Wrong:
Wednesday: This is one day behind Thursday and would require a different shift.

Saturday: This is two days ahead of Thursday and does not match the net one odd day result.

Thursday: This would imply zero odd days between the two birthdays, which is not supported by the calculation.

Common Pitfalls:
Errors commonly occur when students rush the month wise totals or forget to subtract the correct starting day part in April. Another mistake is to overlook that only the remainder after division by 7 matters for the weekday, not the full number of days.

Final Answer:
Therefore, in that same year, the birthday of Aradhya on 20 October falls on Friday.