06/11/2018 11:21 pm
TSD (Time speed and distance)
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Three sprinters X, Y and Z are initially standing at the vertex A of an equilateral triangle ABC of side length ‘a’ units. They start running simultaneously from the point A. X runs from A to B and continue towards C after reaching B. Y runs along the median AD and then continues towards C after reaching D. Z runs from A to C and then towards B after reaching C. If is also known that X reached D, Y reached D and Z reached C all at the same time. What is the distance of Y from D, the moment when X meets Z.
(√3-1)a/2
(√3a)/10
(√3 -1)a/4
3a/8
aniket prajapati 06/11/2018 11:52 pm
since x,y,z reach at D, D, C so the ratio of distance travelled by them will be the ratio of speeds
x:y:z= a+a/2 : √3a/2 : a
= 3:√3:2
now we have to find out the time in which X and Z meet for that we have to take relative speed of X=3+2=5 and assume Z to be still then X has to cover 3a distance to catch Z
time= distance/speed=3a/5
y will cover distance in 3a/5 time= speed *time= √3*3a/5= 3√3a/5
Distance of Y from D= 3√3a/5- √3/2 = √3a/10 (answer)
I am getting this and I am pretty sure I did it right
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15/11/2018 3:29 am
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02/12/2018 11:43 am
TG Team 02/12/2018 2:24 pm
A |_____d_______|B
let the time taken by B be t min ,
Time taken by A =. t - 8 min
d/ [d/t + d/(t-8)] = 3
t(t-8)/(t-8+t) = 3
t^2 - 8t = 6t - 24
t = 12 or 2 , 2 is inadmissible
Hence , time taken by A to cover the distance 'd' = 12 - 8 = 4min
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04/12/2018 11:10 pm
TG Team 05/12/2018 2:34 pm
P ---------------------------Q
Time taken by Deepak to travel 20km : 2hours
Time taken by Sandeep to travel 20km : 1 hour
Time taken by Pawan to travel 20km: 2/3 hour
LCM : [ 2,1,2/3 ] = 2
They meet at P after every 2 hours Hence , 12hours /2 = 6 times .
They never meet at Q.
Hence , 6 times
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06/12/2018 7:12 pm
Hello sir , kindly share the solution to this problem-
A started to chase B when B was 27 steps ahead of A. B takes 8 steps for every 5 steps that A takes. 2 steps of A is equal to 5 steps of B. After how many steps did A catch up with B?
TG Team 07/12/2018 12:43 pm
A started to chase B when B was 27 steps ahead of A
here whose 27 steps is given ? A's or B's ?
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30/06/2019 9:53 pm
There are two clocks, which are set to correct time on sunday at 12:00 noon. The first clock gains 5/2 minutes every hour while the second clock loses 3/2 minutes every hour. When will they be 2 hours apart?
1. Monday 9:00 pm
2. Tuesday 12:00 mid-night
3. Monday 6:00 pm
4. Tuesday 6:00 am
Gaurav Jain 02/07/2019 4:08 pm
first clock goes 2.5 mins ahead and second loses 1.5 mins in an hour.
Effectively both clocks are at difference of 4 mins in an hour.
so for 120 mins difference time taken will be 120/4 = 30 hours.
Hence on Monday 6.00 pm
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30/06/2019 9:54 pm
The speed of the boat in still water is 6kmph. What is the speed of the stream (in kmph) if the boat can cover 32km downstream or 16 km upstream in the same time?
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20/07/2019 12:06 am
Angad and Bali traveled on the same road and at the same rate from Delhi to Bhatinda. At the 50th milestone from Bhatinda, Angad overtook a herd of goats which were going at the rate of 1.5 miles per hour. Two hours after that Angad met a wagon which was moving at the rate of 2.25 miles per hour. Bali overtook the same herd of goats at the 45th milestone from Bhatinda, and met the wagon exactly 40 minutes before he came to the 31st milestone. How far away from Bhatinda was Bali when Angad reached Bhatinda?
This post was modified 5 years ago by manan
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20/07/2019 12:14 am
One of the ski lifts at Kulu Manali climbs the mountain in a line that parallels one of the ski runs. Both the run and the lift are two km long, and a chair passes the starting point of the lift every 10 seconds. A skier starts her run just as the chair arrives at the top of the lift and another chair starts back down. She arrives at the bottom just as a chair is starting up the mountain and another chair is completing its descent. Counting these two chairs and the two at the start of her run, she sees 97 chairs on their way up the mountain and 61 chairs on their Way down. If the chair that started down the slope at the same time that the skier did is still on its way down when the skier reaches the bottom of the slope, what is the average speed of the skier?
Gaurav Jain 23/07/2019 3:04 pm
the number of chairs that came out on the up line = number of chairs that went inside on the down line
so chairs on line = (97+61)/2 = 79 , So 18 chairs came up and 18 went inside by the time skier reached top to bottom, it took 170 sec, because 1st came up at 0 sec and then 10 sec gap
and hence skier took 170 sec to reach bottom
so 2 km is covered in 170 sec
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12/11/2019 2:34 am
At what time instant after 8 o' clock do the short hand and long hands of a clock enclose the equal angles with the horizontal?
Gaurav Jain 16/11/2019 9:13 am
horizontal line is the line connecting 3 and 9.
Let's say min hand is at x angle from 3, means it has traveled 90-x degrees. after 8 o clock.
and hour hand is at x angle before 9, means it has traveled 30-x in the same time.
now 90-x/(5.5) = 30-x/0.5
Gaurav Jain 16/11/2019 9:13 am
horizontal line is the line connecting 3 and 9.
Let's say min hand is at x angle from 3, means it has traveled 90-x degrees. after 8 o clock.
and hour hand is at x angle before 9, means it has traveled 30-x in the same time.
now (90-x)/(5.5) = (30-x)/0.5
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12/11/2019 2:38 am
Gaurav Jain 16/11/2019 9:09 am
one gains 2.5 mins and other loses 1.5 mins , hence they are 4 mins apart in an hour. So for 120 mins apart, it will take 30 hours.
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16/11/2019 11:54 am
Akbar & Birbal start together on a circular track of 600 m in opposite directions at 6m/s and 4m/s respectively. Every time they meet, they exchange their speeds as well as directions. Find out the shortest distance of their 7th meeting point from the starting point along the track.
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01/03/2020 6:54 pm
