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Reasoning Aptitude

CLOCK MCQs

Clocks

Total Questions : 146 | Page 15 of 15 pages
Question 141. The minute hand of a clock overtakes the hour hand at intervals of 63 min of the correct time. How much does a clock gain or loses in a day?
  1.    54 $8/77$ min (gain)
  2.    56 $8/77$ min (gain)
  3.    53 $8/99$ min (loss)
  4.    54 $8/77$ min (gain)
 Discuss Question
Answer: Option B. -> 56 $8/77$ min (gain)
Answer: (b)
Method I
As we know that in a correct clock, the minute hand gains 55 min spaces over the hour hand in 60 min.
To be together again, the minute hand must gain 60 min over the hour hand.
60 min are gained in $(60/55 × 60) min = 65 5/11 min$
But they are together after 63 min.
Therefore, gain in 63 min =$ (65 5/11 - 63) = 2 5/11 min = 27/11 min$
Gain in 24 h = $(27/11 × 60 × 24/63) min = 4320/77 min = 56 8/77 min$
As result is positive, therefore clock gains 56 $8/77$ min.
Method II
In the given question, x = 63 min
According to the formula,
Required result = $(720/11 - x) (60 × 24 /x) min = (720/11 - 63) (60 × 24 /63 ) min$
= $27/11 × 60 × 8 /21 = 56 8/77 $min (gain as sign in positive)
Question 142. A watch which gains uniformly is 2 minutes low at noon on Monday and is 4 min. 48 sec fast at 2 p.m. on the following Monday. When was it correct?
  1.    2 p.m. on Tuesday
  2.    1 p.m. on Friday
  3.    3 p.m. on Thursday
  4.    2 p.m. on Wednesday
 Discuss Question
Answer: Option D. -> 2 p.m. on Wednesday
Answer: (d)
Time from 12 p.m. on Monday to 2 p.m.
on the following Monday = 7 days 2 hours = 170 hours.
Therefore, the watch gains $(2 + 4 4/5) min. or 34/5 min.$ in 170 hrs.
now, 34/5 min. are gained in 170 hrs.
2 min. are gained in $(170 × 5/34 × 2) hrs = 50 hrs.$
Therefore, Watch is correct 2 days 2 hrs. after 12 p.m. on Monday
i.e. it will be correct at 2 p.m. on Wednesday
Question 143. The minute hand of a clock overtakes the hour hand at intervals of 50 min of the correct time. How much does a clock gain or lose in a day?
  1.    443 $28/55$ min (gain)
  2.    433 $28/55$ min (loss)
  3.    445 $5/55$ min (gain)
  4.    444 $28/55$ min (loss)
 Discuss Question
Answer: Option C. -> 445 $5/55$ min (gain)
Answer: (c)
Required result = $(720/11 - x) (60 × 24 /x) min$
Here, x = 50 Therefore, required result = $(720/11 - 50) (60 × 24/50) min$
= $(170/11 × 144/5) min$
= 445 $5/55$ min gain (gain as sign is positive)
Question 144. Between 5 and 6, a lady looked at her watch and mistaking the hour hand for the minute hand, she thought that the time was 57 minutes earlier than the correct time. The correct time was
  1.    24 minutes past 5
  2.    12 minutes past 5
  3.    36 minutes past 5
  4.    48 minutes past 5
 Discuss Question
Answer: Option A. -> 24 minutes past 5
Answer: (a)
Since the time read by the lady was 57 minutes earlier than the correct time,
so the minute hand is (60 - 57) = 3 minute spaces behind the hour hand.
Now, at 5 O' clock, the minute hand is 25 minute spaces behind the hour hand.
To be 3 minute spaces behind, it must gain (25 - 3) = 22 minute spaces.
55 min spaces are gained in 60 min.
22 min spaces are gained in $(60/55 × 22) = 24 min$
Hence, the correct time was 24 minutes past 5.
Question 145. The minute hand of a clock overtakes the hour hand at intervals of 88 min of the correct time. How much does a clock gain or lose in a day?
  1.    368 $112/121$ min (loss)
  2.    369 $112/121$ min (loss)
  3.    368 $112/121$ min (gain)
  4.    369 $112/121$ min (gain)
 Discuss Question
Answer: Option A. -> 368 $112/121$ min (loss)
Answer: (a)
Required result = $(720/11 - x) (60×24 /x) min$
Here, x = 88
Therefore, required result =$ (720/11 - 88) (60×24 /88) min$
= $-248/11 × 180/11 min = -368 112/121 min$ (loss as sign in negative)
Question 146. A watch which gains 5 seconds in 3 minutes was set right at 7 a.m. In the afternoon of the same day, When the watch indicated quarter past 4 O' clock, the true time is
  1.    59 $7/12$ min. past 3
  2.    2 $3/11$ min. past 4
  3.    58 $7/11$ min. past 3
  4.    4 p.m.
 Discuss Question
Answer: Option D. -> 4 p.m.
Answer: (d)
Time from 7 a.m. to 4.15 p.m. = 9 hrs 15 min = $37/4$ hrs 3 min 5 sec of this clock = 3 min. of the correct clock.
= $37/720$ hrs of this clock = $1/20$ hrs of the correct clock
= $37/4$ hrs of this clock
= $(1/20 × 720/37 × 37/4)$ hrs of the correct clock
= 9 hrs of the correct clock
Therefore, The correct time is 9 hrs after 7 a.m., i.e. 4 p.m.

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