Aptitude - Clock - Discussion

Discussion Forum : Clock - General Questions (Q.No. 6)
6.
At what time between 7 and 8 o'clock will the hands of a clock be in the same straight line but, not together?
5 min. past 7
5 2 min. past 7
11
5 3 min. past 7
11
5 5 min. past 7
11
Answer: Option
Explanation:

When the hands of the clock are in the same straight line but not together, they are 30 minute spaces apart.

At 7 o'clock, they are 25 min. spaces apart.

Minute hand will have to gain only 5 min. spaces.

55 min. spaces are gained in 60 min.

5 min. spaces are gained in 60 x 5 min = 5 5 min.
55 11

Required time = 5 5 min. past 7.
11

Discussion:
68 comments Page 1 of 7.

Nanthakumar said:   2 weeks ago
Simple method.

55 = 60.
Then 5 = x.
55x= 300.
x=300/55.
x= 5 5/11.

Rohit Joshi said:   4 months ago
As the clocks are in a straight line but not together, the angle formed by the hands of the clock will be 180.

Now, We know that Angle = |30*Hours - 11/2*Minutes|
Therefore, 180 = 30*7 * 11/2 * Minutes.
210 - 180 = 11/2 * Minutes.
30 = 11/2 * Minutes.
60/11 = Minutes.
55 * 5/11 = Minutes.
So, finally, the answer is D.
(4)

Tushar said:   1 year ago
To calculate the angle between hr hand and min hand.
we have formula ->> 30*Hours-11/2*minutes.

In the above question, they said that minute and hour hands are in one line but not together means Angel between them should be 180°.
:: 30 * 7 - 11/2 * x = 180°.
Then, x = 5.4545 ~5 + 5/11.
(24)

Mohit Sharma said:   3 years ago
θ = { hour * 30 } diff { min * 11/2 } take difference between greater value and smaller value.

Now for the straight line, we know θ = 180.

We can put all these values in the formula

Hour = 7
θ = 180
min = ?

θ = hour * 30 diff min * 11/2.
180 = { 7 * 30 } diff { min* 11/2}.
180 = { 210 } diff { min* 11/2},
min = 2/11 * 210-180,
min = 60/11.

which is equal to 5 5/11.
(3)

Ashwini said:   3 years ago
60/55 I don't get this step. Please anyone explain.

Bangya said:   4 years ago
Assume that the time is 1 O'clock. If we look in a clockwise direction, it's 55 min space but if we look in the anticlockwise direction, it's 5-minute space. Can somebody explain which direction should we look to know the correct minute space?

If both directions are correct, then 5-minute space will be equal to 55-minute space.

Santhoshi vempati said:   4 years ago
The angle between minute's hand hour's hand=30H-(11/2)M.
H = hours; M = minutes.

Given hour's and minute's is a straight line, so the angle is 180degrees.
180 = 30(7) - (11/2) * M,
M = 60/7 = 5 5/11,
So, the answer is 5 5/11min.past 7.
(4)

Ajeesh R Nair said:   4 years ago
@Himanshu

How min hand increases angle? Please explain.

Dara. Sai Madhukar said:   4 years ago
This question is solved by using formula.

A=30*HOUR -5.5*MINUTES.

Here we aer going to take A =180 degrees (straight line).
180=30*7-5.5*M.
M is minutes.
(1)

Sonia said:   4 years ago
At 7:05 both hands of the clock make a straight line.

So by taking 5 minutes use formula (5*12/11), that's it.


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