Aptitude - Clock - Discussion

@All.

To those who say option A is correct.

1. Total minutes as per the time shown by the watch from 7.00 am to 4.15 pm
555 minutes.
(these 555 minutes also include the 5 sec. gained by the watch every 3 minutes.
Most people have failed to adjust to the same.)

2. Let's see how to adjust to nullify the 5 seconds gained every three minutes to arrive at the correct answer.
Every three minutes, the watch gains 5 seconds.
3 minutes = 180 seconds.
So, 555minutes * 180/185 =540 minutes.

NOTE: This step can be solved in many different ways. for eg, instead of converting 3 minutes in 180 seconds, you can keep them as it is and instead say gains per minute is 1.66666667 seconds. etc.

3. Final answer 7.00 am + 540 minutes = 4.00 pm.

THE CORRECT ANSWER IS OPTION(A)

Step 1: Find total gain per minute

Given: 5 sec gain in 3 min
Gain per minute = 5/3 sec

Step 2: Find total time shown by watch
From 7:00 a.m. to 4:15 p.m. = 555 minutes

Step 3: Find total gain in that time,
Total gain = 555 × 5/3.
= 925 sec.

Convert:
925 sec = 15 min 25 sec.

Step 4: Subtract gain from shown time,

Watch is fast, so:
Real time=4:15−15 min 25 sec.
= 3:59:35 p.m.
converting to mixed fraction give us answer as 3:59:35/60 that is equals to 3:59:7/12.

I think 59 (7/12) past 3.

So, Option A is correct.

The answer is A.

A lot of people are ignoring the extra 25 seconds.
The exact time gained is 925 seconds.
(This is best explained in the comment down below)
900 seconds is 15 minutes. So, we deduct 15 minutes from the time given.
ADDITIONALLY, 25 seconds also will be deducted -
60 - 25 = 35 seconds remaining.
Hence, 35/60 which explains the extra 7/12.

The final answer is -> 59 7/12 minutes past 3.

Gain:
3 minutes 5 sec,
15 minutes 25 sec,
30 minutes 50 sec,
60 min( 1 hour) 100 sec.

Then, 7 to 4:15 - 9 hours 15 minutes.
Per hour 100 sec= 900.
And 15 minutes 25 sec.
Total - 925 sec.
925 sec ÷ 60 = 15 minutes.
(15 mins is extra).
9 hours 15 - 15 minutes 9 hours.
7 AM to 4 PM (9 hours).
So, the answer is 4 PM.

For 3 mins it gains 5 seconds.

Then for 925 minutes (9hr 15 min) it gains 15 mins 25 seconds.

So, subtract 15 mins 25 seconds from 4:15.
We will get 3:59:35 which is 59* (7/12) mins past 3.

Thank you everyone for explaining the answer.

It gains 5 seconds in 3 minutes.

3min = 5seconds
3min = 1/12 min
1min = 1/36 min

Let correct watch shows time which is x min ahead of 7 am.

Then minutes gained by faulty clock = x/36minutes.

So, the faulty clock is ahead of 7 am by (x + x/36)min or 37x/36 min.

but in question, it is given faulty clock shows 4.15 pm which is (9*60+15)min or 555min ahead of 7 am.

So,
37x/36 = 555

x = 540min or 9 hrs

So, the correct time is 7 am + 9hr = 4 pm.

Note: We have to calculate the time gained by the faulty clock in terms of the correct clock not in terms of the faulty clock time given in the question

3 min - 5 sec.
30 min - 50 sec.
60 min - 100 sec. [ 1 hour - 100 sec]
9 hours - 900 sec [900 sec = 15 min ].

The clock is showing 4:15 and we know that it gained 15 mins
Therefore it must the real-time is 4 pm.

The right answer is option A.