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Reasoning Aptitude

CLOCK MCQs

Clocks

Total Questions : 146 | Page 6 of 15 pages
Question 51. There are two clocks, both set to show 10 pm on 21st January 2010. One clock gains 2 minutes in an hour and the other clock loses 5 minutes in an hour. Then by how many minutes do the two clocks differ at 4 pm on 22nd January 2010?
  1.    126 minutes
  2.    136 minutes
  3.    96 minutes
  4.    106 minutes
 Discuss Question
Answer: Option A. -> 126 minutes
Answer: (a)
One clock show 10 pm.
On 21st January 2010 one clock gains = 2 minutes
Other clock loses = 5 minutes
Time period between 10 pm and 4 pm = 18 hours
Therefore, Required difference = (2 × 18 + 5 × 18) minutes = 126 minutes
Question 52. London time is five and a half hours behind Delhi time. What time is it in London if it is 0.2.35 in Delhi?
  1.    8.05
  2.    21.35
  3.    21.05
  4.    7.05
 Discuss Question
Answer: Option C. -> 21.05
Answer: (c)
Clearly, time in London is 5 hrs 30 minutes behind 2.35 a.m. which is 9.05 p.m. or 21.05 hrs.
Question 53. Wall clock gains 2 minutes in 12 hours, while a table clock loses 2 minutes every 36 hours. Both are set right at 12 noon on Tuesday. The correct time when both show the same time next would be
  1.    12:30 at night, after 130 days
  2.    12 noon, after 135 days
  3.    12 midnight after 135 days
  4.    1:30 at nights, after 130 days
 Discuss Question
Answer: Option B. -> 12 noon, after 135 days
Answer: (b)
After 12 days, i.e., after 12 × 24 hours clock A will gain 48 minutes and will show 12:48 noon.
After 12 days, i.e., after 12 × 24 hours clock B will lose 16 minutes and will show 11:44 am.
The two clocks will show the same time after 135 days The time difference has to be 12 hours between then = 720 minutes.
A will gain 540 minutes in 135 days. B will lose 180 minutes in 135 days Total 720 minutes.
Further if we consider only time then the problem becomes simpler Total difference of minutes between the times shown by the clocks after 36 hours = $16/3$ minutes difference in 1 day = 12 × 60 minutes difference in $3/16$ × 12 × 60 = 135 days.
Question 54. I have two watches with a 12 hour cycle. One of them gains one minute a day and the other loses 1$1/2$ minute per day. If I set them both at the correct time, how long will it be before they again tell the correct time together?
  1.    720 days
  2.    288 days
  3.    480 days
  4.    1440 days
 Discuss Question
Answer: Option D. -> 1440 days
Answer: (d)
Clearly, the first watch will show the correct time when it has gained 12 hours
i.e., (12 × 60) = 720 min and the second watch will show the correct time when it has lost 720 min.
Time taken by first watch to gain 720 min = 720 days.
Time taken by second watch to gain 720 min = (720 ÷ 1 $1/2$) days = (720 × $2/3$ days) = 480 days.
So the first watch shows correct time after every 720 days and the second watch after every 480 days.
Therefore, Time after which both the clocks will together tell the correct time = L.C.M. of 720 and 480 = 1440 days.
Question 55. Raveena left house for the bus stop 15 min earlier than usual. It takes 10 min to reach the stop. She reached the stop at 8 : 40 am. What time does he usually leave home for the bus stop?
  1.    8:30 AM
  2.    8:45 AM
  3.    8:55 AM
  4.    8:05 AM
 Discuss Question
Answer: Option B. -> 8:45 AM
Answer: (b)
Clearly, Raveena left home 10 min before 8 : 40 am i.e., at 8 : 30 am
but it was 15 min earlier than usual,
so she usually leaves for the stop at (8 : 30 + 0 : 15) = 8 : 45 am.
Question 56. A bus for Delhi leaves every 30 min from a bus stand. An enquiry clerk, Ram told Shyamlal, a passenger that the bus has already left 10 min ago and the next bus will leave at 9 : 35 am. At what time did the enquiry clerk give this information to Shyamlal?
  1.    9:10 AM
  2.    9:15 AM
  3.    9:20 AM
  4.    9:05 AM
  5.    9:25 AM
 Discuss Question
Answer: Option B. -> 9:15 AM
Answer: (b)
As next bus leaves at 9 : 35 am.
Therefore, Previous bus left at (9 : 35 - 0 : 30) = 9 : 05 am.
The time when enquiry clerk gave this information = 9 : 05 + 0 : 10 = 9 : 15 am.
Question 57. There are 20 people working in an office. The first group of five works between 8 am and 2 pm. The second group of ten works between 10 am and 4 pm and the third group of five works between 12 noon and 6 pm. There are three computers in the office which all the employees frequently use. During which of the following hours, the computers are likely to be used the most?
  1.    2 : 00 pm - 4 : 00 pm
  2.    1 :00 pm - 3 : 00 pm
  3.    12 noon -2 : 00 pm
  4.    10 am - 12 noon
 Discuss Question
Answer: Option C. -> 12 noon -2 : 00 pm
Answer: (c)
It is obvious that computers would be used most when all the three groups are working simultaneously and this happens during the period 12 noon to 2 pm.
Question 58. The train for Chandigarh leaves every two and a half hour from New Delhi Railway Station. An announcement was made at the station that the train for Chandigarh had left 40 min ago and the next train will leave at 18 h. At what time was the announcement made?
  1.    17 : 05 h
  2.    17 : 25 h
  3.    16 : 10 h
  4.    15 : 30 h
 Discuss Question
Answer: Option C. -> 16 : 10 h
Answer: (c)
Time of the last train leaving the station = (18 : 00 - 2 : 30) h = 15 : 30 h
But this happens 40 min before the announcement is made.
Therefore, Time of making announcement = (15 : 30 + 0 : 40) = 16 : 10 h.
Question 59. The priest told the devotes, "the bell is rung at regular intervals of 45 min. The last bell was rung 5 min ago. The next bell is due to the rung at 7 : 35 am. At what time did the priest give the information to be devotes?
  1.    7:40 AM
  2.    7:00 AM
  3.    7:05 AM
  4.    6:55 AM
 Discuss Question
Answer: Option C. -> 7:05 AM
Answer: (c)
Time of ringing last bell = (7 : 45- 0 : 45) = 7 : 00 am.
But it happened 5 min before the priest gave the information to the devotes.
Therefore, Time of giving information = 7 : 00 + 0 : 05 = 7 : 05 am.
Question 60. In an accurate clock, in a period of 2 hours 20 minutes the minute hand will move over
  1.    140°
  2.    320°
  3.    520°
  4.    840°
 Discuss Question
Answer: Option D. -> 840°
Answer: (d)
Angle traced by the minute hand in 2 hrs 20 min,
i.e., 140 min = $(360/60 × 140)^o= 840°$

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