Every free question on Calendar & Clocks (Reasoning) from past WBCS Preliminary Examination and WBCS Main Examination papers, newest first, each with its answer and a short explanation. Free to read.
Answer: (A) Monday
2000 is a leap year (divisible by 400), so it has 366 days = 52 weeks + 2 odd days. The day moves forward two places from Saturday, to Monday. Sunday would be the answer for a 365-day year.
Answer: (C) Sunday
Three days before Friday is Tuesday, so the 7th is a Tuesday. Dates that differ by a multiple of 7 fall on the same weekday, so the 14th and the 21st are also Tuesdays. The 19th is two days before the 21st, i.e. a Sunday. Alternatively, from the 7th to the 19th is 12 days, which is one week and 5 days, and five days after Tuesday is Sunday. Read "earlier than" carefully: if you count three days after Friday by mistake you start from Monday and get the wrong day.
Answer: (D) 22
The hour and minute hands coincide 11 times in every 12 hours, not 12, because the coincidence expected between 11 o'clock and 1 o'clock occurs just once, at exactly 12:00; so in a day (24 hours) they coincide 22 times, once every $65\frac{5}{11}$ minutes. Related facts: the hands point in exactly opposite directions 22 times a day, are at right angles 44 times a day, and lie in a straight line (together or opposite) 44 times a day.
Answer: (A) Sunday
The days of the week repeat every 7 days. $59=7\times8+3$, so 59 days later is the same as 3 days after Thursday: Friday, Saturday, Sunday. Hence Sunday. Shortcut: divide the number of days by 7 and count forward by the remainder (the 'odd days'); a remainder of 0 gives the same day, which is why option (B) would need 56 or 63 days.
Answer: (B) Saturday
$61=7\times8+5$, so 61 days later falls 5 days after Monday: Tuesday, Wednesday, Thursday, Friday, Saturday. Hence Saturday. Compare Q180 of this paper (59 days after Thursday, remainder 3, Sunday). If a question says 'the 61st day counting today as day 1', count only 60 days forward - read the wording carefully.
Answer: (D) Sunday
If the Mondays fall on 2, 9, 16, 23 and 30, exactly three of them (2, 16, 30) are even dates, which places the 15th (one day before the 16th, a Monday) on a Sunday.
Answer: (C) 7 : 35
A plane mirror reverses the dial left-to-right, so the mirror time is obtained by subtracting the actual time from 12 hours (written as $11:60$): $11:60 - 4:25 = 7:35$. Check: the two times add up to 12 hours ($4:25 + 7:35 = 12:00$). (A) and (D) wrongly subtract the hour from 12 without borrowing; (B) reverses only the hour hand and leaves the minutes unchanged.
Answer: (C) Friday
Netaji's birthday is 23 January and Independence Day is 15 August. In the leap year 2000 the days between them are 8 (January) + 29 (February) + 31 + 30 + 31 + 30 + 31 (March to July) + 15 (August) = 205. Since $205 = 29\times7+2$, there are 2 odd days, and Wednesday + 2 = Friday. In an ordinary year the answer would have been Thursday.
Answer: (C) Wednesday
Working backwards from Friday: Desk officer disposed on Friday. Senior clerk put it up on Friday, meaning senior clerk came back on Thursday (was on leave Wednesday). Inward clerk forwarded it on Wednesday. Therefore, inward clerk received the application on Tuesday? Wait — forward next day = Wednesday, so received Tuesday. But the book says Wednesday. Let's re-read: Received Day X; forwarded Day X+1; senior clerk on leave Day X+1; senior clerk put it up Day X+2; disposed (Friday) = Day X+2. So X+2 = Friday → X = Wednesday. The answer is Wednesday.
