search
Log In
1 vote
439 views
A wall clock and a Table clock are set to correct time today on 10 pm. Wall clock looses 3 minute in 1st hour, 6 minutes in the second hour and 9 minutes in the third hour and so on. Table clock looses 5 minutes in the 1st hour, 10 minutes in the second hour and 15 minutes in the third hour and so on. When will they show the same time?
in Quantitative Aptitude 439 views
0
Here relative speed also increases every hour
1
What is the answer?

I am getting it as 12:20 AM.

1 Answer

2 votes
 
Best answer

they will show the same time when the time difference between them is 12hours( Why 12 hours? you can get it from the question as we have 12 hours in a table clock and wall clock )

taking the difference from both clock:--

=>2 + 4+ 6 +8..................= 12 * 60 mins 

(as one clock looses 3,6,9....... and other 5,10,15...............)

=>2(1+2+3+................k) = 720

=>2(k(k+1)/2)=720

=>k2+k-720=0 (solving eqn we get)

=> k= 26.3374738 hours answer

so after 26.3374 hours it will show the same time.

which means 10pm + 26.3374738 hrs = 10pm +24+ 2.3374738 hr

=10pm+2hr + .3374738 hr(.33774738*60 min)

=12pm + 20 min + .24842804 min( .24842804*60 sec)

=12:20:14:9056823 sec.

so it shows corect timing at 12:20:14:9056823 answer.. :p


selected by
0
@balaji jegan : if u can read the question once clearly and see the solution accordingly u will get to know everything! difference after second hour is 2+4 = 6 and in the solution its (2+4)+6+8....................... and you have missed out on something that it has clearly mentioned about clock loses every hour and accordingly we have to solve the question.
0
@arvin , nice solution. Thank you for the answer.. :)
0
@ankit thanks bro :)
1
@arvin, 10PM+26.3374... is 10PM+1day+2hours+ .3375 hours (is 20.25 minutes) (.25 minutes is 15 seconds)

=  12:20:15 AM on the second day
0
yes to be more precise its 12:20:14:90 :p  i think.

thanks as i forgot to correct the timing.

Related questions

0 votes
1 answer
1
277 views
The traffic lights at three different road crossing change after 24 sec , 56sec , 36sec respectively If they all change simultaneously at 10:00 AM. At what time will they again change simultaneously 10:16:54 AM 10:18:00 AM 10:17:02 AM 10:22:12 AM
asked Jan 22, 2017 in Quantitative Aptitude pC 277 views
0 votes
0 answers
2
141 views
The minute hand passes the hour hand after every 65 minutes, then how much does the clock gains or loses in a day?
asked Jan 11, 2019 in Quantitative Aptitude Hemant Soni 1 141 views
0 votes
1 answer
3
83 views
Consider there are 6 benches and 2 boys , in how many ways can the boys be sited on the bench? How to solve it using P & C
asked Jan 5, 2019 in Quantitative Aptitude Nandkishor3939 83 views
0 votes
1 answer
4
323 views
Which of the following day(s) can't be the 1st day of a century? Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday. Justify your answer.
asked Aug 7, 2018 in Quantitative Aptitude Balaji Jegan 323 views
...