Quantitative Aptitude
CLOCK MCQs
Total Questions : 223
| Page 22 of 23 pages
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
$$\eqalign{
& \Leftrightarrow \frac{{649}}{{30}}{\text{hours}} \cr
& = {\left( {\frac{{360}}{{12}} \times \frac{{649}}{{30}}} \right)^ \circ } \cr
& = {649^ \circ } \cr} $$
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
$$\eqalign{
& \Leftrightarrow \frac{{649}}{{30}}{\text{hours}} \cr
& = {\left( {\frac{{360}}{{12}} \times \frac{{649}}{{30}}} \right)^ \circ } \cr
& = {649^ \circ } \cr} $$
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
$${\text{ = }}\left[ {77 \times \left( {2 \times \frac{{22}}{7} \times 10} \right) - 6\frac{5}{{12}} \times \left( {2 \times \frac{{22}}{7} \times 7} \right)} \right]{\text{cm}}$$
$$\eqalign{
& = \left( {4840 - 282.33} \right){\text{ cm}} \cr
& = 4557.67{\text{ cm}} \cr} $$
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
$${\text{ = }}\left[ {77 \times \left( {2 \times \frac{{22}}{7} \times 10} \right) - 6\frac{5}{{12}} \times \left( {2 \times \frac{{22}}{7} \times 7} \right)} \right]{\text{cm}}$$
$$\eqalign{
& = \left( {4840 - 282.33} \right){\text{ cm}} \cr
& = 4557.67{\text{ cm}} \cr} $$
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
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
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.
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.
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
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
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.
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.
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
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
Answer: Option C. -> 44
In 12 hours, they are at right angles 22 times.
∴ In 24 hours, they are at right angles 44 times.
In 12 hours, they are at right angles 22 times.
∴ In 24 hours, they are at right angles 44 times.
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
$$\eqalign{
& \left( {\frac{{60}}{{55}} \times 50} \right){\text{min}}{\text{.}}\,{\text{or}}\,54\frac{6}{{11}}\,{\text{min}}. \cr
& \therefore {\text{Required}}\,{\text{time}} \cr
& = 54\frac{6}{{11}}{\text{min}}{\text{.}}\,{\text{past}}\,4 \cr} $$
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
$$\eqalign{
& \left( {\frac{{60}}{{55}} \times 50} \right){\text{min}}{\text{.}}\,{\text{or}}\,54\frac{6}{{11}}\,{\text{min}}. \cr
& \therefore {\text{Required}}\,{\text{time}} \cr
& = 54\frac{6}{{11}}{\text{min}}{\text{.}}\,{\text{past}}\,4 \cr} $$
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.
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.