In a certain year, Akarsh's birthday falls on Saturday, 29th July. In the same calendar year, Ojas is born on 12th August. Based on this information, on which day of the week does Ojas's birthday fall in that year?

Introduction / Context:
Calendar aptitude questions often ask you to find the day of the week for a particular date given the weekday for some other date in the same year. This problem involves two birthdays, both in the same year, and you have to track how many days elapse between the two dates and then convert that into a shift in the day of the week.

Given Data / Assumptions:

• Akarsh's birthday is on Saturday, 29th July of a certain year.
• Ojas's birthday is on 12th August of the same year.
• Both dates are in the same calendar year.
• We assume the usual Gregorian calendar with July having 31 days and August having 31 days.
• We need to find the weekday on which 12th August falls.

Concept / Approach:
When two dates are in the same year, the day difference between them depends only on the number of days between those dates, not on which specific year it is. Since both dates (29th July and 12th August) come after February, leap year issues do not affect the difference. Once we know how many days apart they are, we take that number modulo 7 to see how many steps forward we move in the weekly cycle.

Step-by-Step Solution:
Step 1: Note that July has 31 days. Step 2: From 29th July to 31st July, there are 2 remaining days (30th, 31st). Step 3: From 1st August to 12th August, there are 12 days. Step 4: Total distance between 29th July and 12th August = 2 + 12 = 14 days. Step 5: Compute 14 mod 7. Since 14 = 2 * 7, 14 mod 7 = 0. Step 6: A difference of 14 days corresponds to exactly 2 full weeks, so there is no net shift in the day of the week. Step 7: Therefore, 12th August falls on the same weekday as 29th July.

Verification / Alternative check:
Because 14 is a multiple of 7, you can think of moving forward 14 days as landing on the same weekday. For example, starting at Saturday and counting 7 days brings you to the next Saturday, and another 7 days leads to yet another Saturday. Hence after 14 days, the weekday must again be Saturday, confirming that Ojas's birthday is also on Saturday.

Why Other Options Are Wrong:
Wednesday, Friday, Sunday and Monday would correspond to net shifts of 3, 6, 1 or 2 days from Saturday, respectively, none of which match the exact 0-shift implied by a 14-day (two-week) gap. Since the difference between the dates is a whole number of weeks, no weekday other than Saturday is possible.

Common Pitfalls:
Students sometimes miscount the number of days by including or excluding the start date incorrectly. A safe method is to count the days after the first date up to the second. Another mistake is to forget to use modulo 7, and instead try to move 14 steps one by one, increasing chances of error. Always reduce the total day difference modulo 7 to get the effective shift in weekday.

Final Answer:
Ojas's birthday in that same year falls on Saturday.