Latest Elitmus Aptitude Question SOLUTION: ISRO has devised a new digital wrist watch for Abhishek, who will be the first human being to spend 3 Mars years on planet Mars. The watch divides one Mars day into 40 hours, each

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(#M40033068) ELITMUS Numerical Ability question Abhishek's Mars Expedition Keep an EYE

ISRO has devised a new digital wrist watch for Abhishek, who will be the first human being to spend 3 Mars years on planet Mars. The watch divides one Mars day into 40 hours, each hour into 60minutes and each minute into 60 seconds. Abhishek has the habit of glancing at his watch frequently throughout the day (and night). What is the probability that he will see all the digits reading the same (for example, 1 : 11 ) during any single glance? Assume the watch is set to a 20 hour format HH:MM, where four past four PM is shown as 4:04
Option
(a) 1/120
(b) 1/200
(c) 1/240
(d)1/120000

Asked In Elitmus Vivek Jain (10 years ago)

Unsolved Read Solution (12)

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Read Solution (12) :

Sridhar Reddy  (10 years ago)

is it (b)
total prob=40*60=2400
and the events are
1:11
2:22
3:33
4:44
5:55
11:11
total events occured=6*2=12
=>prob=12/2400=1/200

Is this solution Helpfull? Yes (67) | No (9)  

Praveen kumar  (10 years ago)

A)1/120
no.of time he can see is=40*60=2400 (1:00,1:01,...20:59)
events are=20 (1:11,2:22,3:33,....20:20 bcoz wath is in 20 hrs format)
total prob = 20/2400
=1/120
so option (a)1/120 is correct

Is this solution Helpfull? Yes (13) | No (27)  

Brijesh Kumar  (9 years ago)

it is (b) because total prob is 2*20*60=2400
and event which will come
like 111
222
333
444
555
1111
it will come two times in a day
then total event is 2*6=12
and now prob is 12/2400=1/200

Is this solution Helpfull? Yes (10) | No   

Ankit vaidya  (9 years ago)

1:11
2:22
3:33
4:44
5:55
6:66
7:77
8:88
9:99
11:11
=10
=10/60*40
=1/240

Is this solution Helpfull? Yes (7) | No (15)  

madhav  (10 years ago)

why not 6*2/(40*60*60)=1/1200
he can see his watch every second
d is right ans

Is this solution Helpfull? Yes (3) | No (1)  

karthi keyan  (10 years ago)

Why are we not considering 0:00 ?

Is this solution Helpfull? Yes (3) | No   

manivikas  (10 years ago)

I think Sreedhar Reddy is correct bcaz he will see the watch when all the digits are same..

Is this solution Helpfull? Yes (2) | No (2)  

anudeep kumar  (10 years ago)

@ shridhr
wat about 12:12,13:13,14:14,....20:20

Is this solution Helpfull? Yes (2) | No (7)  

rochit ranjan  (9 years ago)

can anyone explain here why 0:00 is not counted ?

Is this solution Helpfull? Yes (1) | No   

Abhijeet Vishnu Agale  (10 years ago)

Pravin Kumar is correct.

Is this solution Helpfull? Yes | No (5)  

Divya gupta  (9 years ago)

plz xplain me dis ??

Is this solution Helpfull? Yes | No (1)  

Vikrant Deshpande  (6 years ago)

Since 4 past 4PM is also given as 4:04 in HH:MM format, the correct possibilities will be:
MORNING (AM):
1:11 , 2:22 , 3:33 , 4:44 , 5:55 , 11:11 .
EVENING (PM):
1:11 , 2:22 , 3:33 , 4:44 , 5:55 , 11:11 .

So overall 12 events out of 40*60 possibilities.
Hence probability = 12/(40*60)
= 1/200 (b).

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