# Aptitude - Clock - Discussion

Discussion Forum : Clock - General Questions (Q.No. 15)

15.

At what time between 9 and 10 o'clock will the hands of a watch be together?

Answer: Option

Explanation:

To be together between 9 and 10 o'clock, the minute hand has to gain 45 min. spaces.

55 min. spaces gained in 60 min.

45 min. spaces are gained in | 60 | x 45 | min or 49 | 1 | min. | |

55 | 11 |

The hands are together at 49 | 1 | min. past 9. |

11 |

Discussion:

47 comments Page 5 of 5.
Krishnadas said:
1 decade ago

@sree. Good work. But is this formula standard?

Shree Hema said:
1 decade ago

@manish

better use this formula

theta=11(m)/2-30(h)

if both hands coincide degree ll be 0

if both hands r in opposite direction degree will be 180

if both hands r in right angle degree will be 90

here it coincides so 0 degree

we have to find min only so keep that parameter(m) as it is, use minimum hour for hour parameter(h=9)

0=11(m)/2-30(9)

m=49 1/11

Got It???

better use this formula

theta=11(m)/2-30(h)

if both hands coincide degree ll be 0

if both hands r in opposite direction degree will be 180

if both hands r in right angle degree will be 90

here it coincides so 0 degree

we have to find min only so keep that parameter(m) as it is, use minimum hour for hour parameter(h=9)

0=11(m)/2-30(9)

m=49 1/11

Got It???

Manish said:
1 decade ago

I don't understand this method please explain it. Why we take 55 min ?

Vipin said:
1 decade ago

Alternative method::

Let the minutes covered when d situation occurs = x

now,

(total degrees covered by minute hand) - (total degrees covered by hr hand)= (outer angle between 12 and 9) i.e.

6x - x/2 = 270

x=540/11 which is our ans. :)

Let the minutes covered when d situation occurs = x

now,

(total degrees covered by minute hand) - (total degrees covered by hr hand)= (outer angle between 12 and 9) i.e.

6x - x/2 = 270

x=540/11 which is our ans. :)

Krish said:
1 decade ago

Sakshi,

The question is between 9 and 10 both the hands must coincide,.

So for the minute hand to reach 9 it has to gain 45 minute spaces.

The question is between 9 and 10 both the hands must coincide,.

So for the minute hand to reach 9 it has to gain 45 minute spaces.

Yamini said:
1 decade ago

Why you take the 55 min spaces ?

Sakshi said:
1 decade ago

How do we know that min? Hand has to gain 45 mins?

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