At a telephone exchange, three phones ring at intervals of 20 sec, 24 sec and 30 seconds. If they ring together at 11 : 25 a.m. When will they next ring together?

Report

Report an issue

Name

Email

Message

Submit

Cancel

RRB Non Technical Exam (Secunderabad) 2016 click here to view all questions

At a telephone exchange, three phones ring at intervals of 20 sec, 24 sec and 30 seconds. If they ring together at 11 : 25 a.m. When will they next ring together?

A11 : 29 a.m.

B11 : 27 a.m.

C11 : 51 a.m.

D12 : 29 p.m.

rahul ? Jan 14 '2020 at 9:33

Correct answer is: 11:27 a.m.

Explanation:

Time taken by three phones to ring together = LCM of 20, 24 and 30

⇒ Time taken by three phones to ring together = 120 seconds

(? 1 min = 60 seconds)

⇒ Time taken by three phones to ring together = \(\frac{120}{60} = 2 \text{ min}\)

If the three phones ring together at 11:25 am then they will next ring together after 2 minutes i.e. at 11:27 am.

∴ Time at which the phones next ring together = 11:27 am

View Answer

Discuss

A clock strikes once at 1 O' clock twice at 2 O'clock thrice 3 O' clock and so, on. How many times will it strikes in 24 hours?

Report

Report an issue

Name

Email

Message

Submit

Cancel

RRB ASSISTANT LOCO PILOT (Allahabad) 2010 click here to view all questions

A clock strikes once at 1 O' clock twice at 2 O'clock thrice 3 O' clock and so, on. How many times will it strikes in 24 hours?

A78

B136

C156

D196

raju ? Dec 23 '2019 at 18:21

Correct answer is: 156

Explanation:

clock strikes once at 1 o'clock, twice at 2o'clock , thrice at 3 o'clock so on.
then clock strikes in 12 hour = 1 + 2 + 3 + ..... + 12 = 78
Therefore clock strikes in 24 hour = 78 X 2 = 156.

View Answer

Discuss

If a watch runs 5 minutes fast every hour, then the angle traversed by a second hand in one minute is-

Report

Report an issue

Name

Email

Message

Submit

Cancel

RRB TC CC Exam (Bangalore) 2006 click here to view all questions

If a watch runs 5 minutes fast every hour, then the angle traversed by a second hand in one minute is-

A360

B360.5

C390

D380

Sachin Khr ? Nov 18 '2016 at 21:21

Answer is : 390
The second hand must traverse 5 * 360° = 1800° more in an hour than it should if it runs 5 minutes fast....
so,in one "normal" minute....it must traverse 1/60th of this plus its normal turn of 360°.......
\(so.... [360 + \frac{1800}{60}]° = [ 360 + 30]° = [ 390]°\)

View Answer

Discuss

A clock strikes once at 1 O' clock, twice at 2 O' clock

Report

Report an issue

Name

Email

Message

Submit

Cancel

RRB TC CC Exam (Patna) 2006 click here to view all questions

A clock strikes once at 1 O' clock, twice at 2 O' clock, thrice at 3 O' clock and so on. What is the total number of striking in a day?

A156

B146

C136

D166

Akilesh Kharvi ? Nov 5 '2016 at 11:0

Answer is: 156
If it's the total number of strikes, then it's 1 + 2 +3....+ 12 all multiplied by 2, because we are calculating it for a day (24 hours).
For Calculating purpose
First 12 Hours is => 1 2 3 4 5 6 7 8 9 10 11 12
Next 12 Hours is => 12 11 10 9 8 7 6 5 4 3 2 1
-------------------------------------------------------------------------------------------------
Total 24 Hours is => 13 13 13 13 13 13 13 13 13 13 13 13 
------------------------------------------------------------------------------------------------
=>13 *12
=>156

View Answer

Discuss

It is between 3 PM and 4 PM and the distance between the

Report

Report an issue

Name

Email

Message

Submit

Cancel

RRB TC CC Exam (Patna) 2006 click here to view all questions

It is between 3 PM and 4 PM and the distance between the hour and the minute hands of colck is 18 minutes space. What time does the clock show?

A3.12 PM

B3.31 PM

C3.27 PM

D3.36 PM

No answer description available for this question. Let us discuss.

View Answer

Discuss