New Questions to solve.?

[assignus]

Originally Posted by jockey

if they are interchanging their position that means together they have cover 360 degrees. as hour hand has taken min hands position and vice- versa. min hand moves 6 deg and hour hand moves 1/2 deg in a min, together they move 13/2 deg in a min.

in 1 min they are moving 13/2 deg

so together 1 deg they will be moving in 2/13 min

so 360 deg in 360 x 2/13 min i.e 720/13 min

yeah..this is quite useful

[sbhaskaran2k]

Hi One more question of same type. .


1) At 12 noon, A starts by car from P and reaches Q which is 120 km away in 4 hrs. B Starting at Q at 1 p.m can reacah p at 3-40 p.m. When will the distance between then is 7.5 kms..

[gauri_j3]

6 min past 2 o clock

ratio of speeds of a and b is 30:45 ie 2:3

from 12 to 1, a travels 30 km .so now distance between them is 90 km.from 1to 2, a travels 30 km and b travels 45km.now the distance bet them is 15 km.

to keep a distance of 7.5 km they need to travel 7.5 km.

b travels at 3/5*7.5=4.5 km and a travels the other 3 km

b travels 45 km in 60 min so he travels 4.5 km in 6 min.



regards,

gauri

Originally Posted by sbhaskaran2k

Hi One more question of same type. .


1) At 12 noon, A starts by car from P and reaches Q which is 120 km away in 4 hrs. B Starting at Q at 1 p.m can reacah p at 3-40 p.m. When will the distance between then is 7.5 kms..

[13th]

Originally Posted by gauri_j3

6 min past 2 o clock

ratio of speeds of a and b is 30:45 ie 2:3

from 12 to 1, a travels 30 km .so now distance between them is 90 km.from 1to 2, a travels 30 km and b travels 45km.now the distance bet them is 15 km.

to keep a distance of 7.5 km they need to travel 7.5 km.

b travels at 3/5*7.5=4.5 km and a travels the other 3 km

b travels 45 km in 60 min so he travels 4.5 km in 6 min.



regards,

gauri

yeah 2.06 pm and 2.18 pm too

[GauravShah]

Originally Posted by sbhaskaran2k

Hi One more question of same type. .

1) At 12 noon, A starts by car from P and reaches Q which is 120 km away in 4 hrs. B Starting at Q at 1 p.m can reacah p at 3-40 p.m. When will the distance between then is 7.5 kms..

Speed of A ... 120/4 = 30 Km/hr.
Speed of B ... 120/(160/60) = 120*60/160 = 45 Km/hr

At 1 pm, A has travelled 30 Kms. So he is 90 Kms from B when B Starts.

Now since both are moving towards each other, the relative speed is (30+45) = 75 Km/hr.

So in 1 hr and 12 mins, they will meet each other i.e. at 2:12 pm.

There are two instances when there is 7.5 Kms between them.

When they are moving together, they cover 75 kms in 1 hr, so 7.5 kms are covered in 6 mins.

So 6 mins before and after they meet, there is 7.5 kms between them.

Time being 2:06 pm and 2:18 pm

HTH

Gaurav.

[shivasmiles]

Originally Posted by sbhaskaran2k

Hi One more question of same type. .


1) At 12 noon, A starts by car from P and reaches Q which is 120 km away in 4 hrs. B Starting at Q at 1 p.m can reacah p at 3-40 p.m. When will the distance between then is 7.5 kms..

The distance between must be 120-7.5 = 112.5


Now d1 = 30*t + 360(t-1)/8 = 112.5

Solving this we get 2.1 hr i.e. 2.06 pm

[sindhb]

After calculating amount of time she remain outside i.e 360/13,
i.e. angle b/w hands is 360/13.

start time = time when hands meet + time to make angle b/w hands 360/13

Next time hands meet when time is 4 4/11 i.e 48/11 hr = 2880/11 min.

For every 1 min angle b/w hands changes by 5.5 degrees.
? ---------------> 360/13 degrees

= 720/143 min

Therefore, 720/143 + 2880/11 = 266.85 min = 4 hr 26.85min.

anybody please correct me if any mistake......

[nikhilkulk]

Originally Posted by sindhb

After calculating amount of time she remain outside i.e 360/13,
i.e. angle b/w hands is 360/13.

start time = time when hands meet + time to make angle b/w hands 360/13

Next time hands meet when time is 4 4/11 i.e 48/11 hr = 2880/11 min.

For every 1 min angle b/w hands changes by 5.5 degrees.
? ---------------> 360/13 degrees

= 720/143 min

Therefore, 720/143 + 2880/11 = 266.85 min = 4 hr 26.85min.

anybody please correct me if any mistake......

Please look at the date of the last post.. It is more than 2 years old
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~Nikhil