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Quantitative Aptitude

CLOCK MCQs

Total Questions : 223 | Page 22 of 23 pages
Question 211. At 9 : 38 A.M. through how many degrees the hour hand of a clock moved since noon the previous day ?
  1.    323°
  2.    612°
  3.    646°
  4.    649°
 Discuss Question
Answer: Option D. -> 649°
Time from 12 noon to 9 : 38 A.M.
= 12 hours + 9 hours 38 minutes
= 21 hours 38 minutes
$$\eqalign{
& {\text{ = 21}}\frac{{38}}{{60}}{\text{ hours}} \cr
& {\text{ = 21}}\frac{{19}}{{30}}{\text{ hours}} \cr
& {\text{ = }}\frac{{649}}{{30}}{\text{hours}} \cr} $$
Angle traced by the hour hand in 12 hours = 360°
Angle traced by the minute hand in
$$\eqalign{
& \Leftrightarrow \frac{{649}}{{30}}{\text{hours}} \cr
& = {\left( {\frac{{360}}{{12}} \times \frac{{649}}{{30}}} \right)^ \circ } \cr
& = {649^ \circ } \cr} $$
Question 212. The hands of a clock are 10 cm and 7 cm respectively. The difference between the distance traversed by their extremities in 3 days 5 hours is = ?
  1.    4552.67 CM
  2.    4555.67 CM
  3.    4557.67 CM
  4.    4559.67 CM
 Discuss Question
Answer: Option C. -> 4557.67 CM
Number of rounds completed by the minute hand in 3 days 5 hours
$$\eqalign{
& = \left( {3 \times 24 + 5} \right) \cr
& = 77 \cr} $$
Number of rounds completed by the hour hand in 3 days 5 hours
$$\eqalign{
& = \left( {3 \times 2 + \frac{5}{{12}}} \right) \cr
& = 6\frac{5}{{12}} \cr} $$
∴ Difference between the distance traversed
$${\text{ = }}\left[ {77 \times \left( {2 \times \frac{{22}}{7} \times 10} \right) - 6\frac{5}{{12}} \times \left( {2 \times \frac{{22}}{7} \times 7} \right)} \right]{\text{cm}}$$
$$\eqalign{
& = \left( {4840 - 282.33} \right){\text{ cm}} \cr
& = 4557.67{\text{ cm}} \cr} $$
Question 213. 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
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
∴ Required difference
= (2 × 18 + 5 × 18 ) minutes
= 126 minutes
Question 214. 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.    12 minutes past 5
  2.    24 minutes past 5
  3.    36 minutes past 5
  4.    48 minutes past 5
 Discuss Question
Answer: Option B. -> 24 minutes past 5
Since the time read by the lady was 57 minutes earlier than the correct time, so the minute hand is (60 - 57) = 3 minutes spaces behind the hour hand.
Now, at 5 o'clock, the minute hand is 25 minutes spaces behind the hour hand.
To be 3 minutes spaces behind, it must gain (25 - 3) = 22 minutes spaces.
55 minutes spaces are gained in 60 minutes.
22 minutes spaces are gained in $$\left( {\frac{{60}}{{55}} \times 22} \right)$$   = 24 minutes
Hence, the correct time was 24 minutes past 5.
Question 215. Henry started a trip into the country between 8 am and 9 am when the hand of clock were together, He arrived at his destination between 2 pm and 3 pm when the hands of the clock were exactly 180° apart. How long did he travel ?
  1.    6 hours
  2.    7 hours
  3.    9 hours
  4.    11 hours
 Discuss Question
Answer: Option A. -> 6 hours
To be together between 8 am and 9 am, the minute hand has to gain 40 minutes spaces.
55 minutes spaces are gained in 60 minutes.
40 minutes space are gained in $$\left( {\frac{{60}}{{55}} \times 40} \right)$$  minutes = $${\text{43}}\frac{7}{{11}}$$  minutes
So, Henry started his trip at $${\text{43}}\frac{7}{{11}}$$  minutes past 8 am.
Now, to be 180° apart, the hands must be 30 minutes spaces apart.
At 2 pm, they are 10 minutes spaces apart.
∴ The minute hand will have to gain (10 + 30) = 40 minutes spaces.
As calculate above, 40 minutes spaces are gained in $${\text{43}}\frac{7}{{11}}$$  minutes.
So, Henry's trip ended at $${\text{43}}\frac{7}{{11}}$$  minutes past 2 pm
∴ Duration of travel = Duration from $${\text{43}}\frac{7}{{11}}$$  minutes past 8 am to $${\text{43}}\frac{7}{{11}}$$  minutes past 2 pm = 6 hours
Question 216. In every 30 minutes the time of a watch increases by 3 minutes. After showing the correct time at 5 am , what time will the watch show after 6 hours ?
  1.    10 : 54 am
  2.    11 : 30 am
  3.    11 : 36 am
  4.    11 : 42 am
  5.    11 : 38 pm
 Discuss Question
Answer: Option C. -> 11 : 36 am
Time gained in 1 hour = 6 minutes
Time gained in 6 hours = (6 × 6) minutes = 36 minutes
After 6 hours, the correct time is 11 : 00 am and the watch will show 11 : 36 am.
Question 217. A watch is 1 minute slow at 1 pm on Tuesday and 2 minutes fast at 1 pm on Thursday. When did it show the correct time = ?
  1.    1 : 00 am on Wednesday
  2.    5 : 00 am on Wednesday
  3.    1 : 00 pm on Wednesday
  4.    5 : 00 pm on Wednesday
 Discuss Question
Answer: Option B. -> 5 : 00 am on Wednesday
Time from 1 pm on Wednesday to 1 pm on Thursday = 48 hours
So, the watch gains (1 + 2) minute or 3 minutes in 48 hours.
Now, 3 minutes are gained in 48 hours
So, 1 minute is gained in $$\left( {\frac{{48}}{3}} \right)$$   = 16 hours.
Thus, the watch showed the correct time 16 hours after 1 pm on Tuesday, i.e., 5 am on Wednesday
Question 218. How many times are the hands of a clock at right angle in a day?
  1.    22
  2.    24
  3.    44
  4.    48
 Discuss Question
Answer: Option C. -> 44
In 12 hours, they are at right angles 22 times.
∴ In 24 hours, they are at right angles 44 times.
Question 219. At what time between 4 and 5 o'clock will the hands of a watch point in opposite directions?
  1.    45 min. past 4
  2.    40 min. past 4
  3.    $$50\frac{4}{{11}}$$ min. past 4
  4.    $$54\frac{6}{{11}}$$ min. past 4
 Discuss Question
Answer: Option D. -> $$54\frac{6}{{11}}$$ min. past 4
At 4 o'clock, the hands of the watch are 20 min. spaces apart.
To be in opposite directions, they must be 30 min. spaces apart.
∴ Minute hand will have to gain 50 min. spaces.
55 min. spaces are gained in 60 min.
50 min. spaces are gained in
$$\eqalign{
& \left( {\frac{{60}}{{55}} \times 50} \right){\text{min}}{\text{.}}\,{\text{or}}\,54\frac{6}{{11}}\,{\text{min}}. \cr
& \therefore {\text{Required}}\,{\text{time}} \cr
& = 54\frac{6}{{11}}{\text{min}}{\text{.}}\,{\text{past}}\,4 \cr} $$
Question 220. How many times in a day, are the hands of a clock in straight line but opposite in direction?
  1.    20
  2.    22
  3.    24
  4.    48
 Discuss Question
Answer: Option B. -> 22
The hands of a clock point in opposite directions (in the same straight line) 11 times in every 12 hours. (Because between 5 and 7 they point in opposite directions at 6 o'clcok only).
So, in a day, the hands point in the opposite directions 22 times.

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