Official Quant thread for CAT 2013

MBA CAT 2024
30349
@mailtoankit said:
1) when two bodies start moving towards each other, then the total distance covered by them for the nth meeting = D + ((n-1)*2D) = (2n - 1)D2) when two bodies start moving towards the same direction, then for the nth meeting they will cover together (n*2D) distancePS : ek book mein padha tha..
do u think this formula is valid when speed of one of them is greater that twice the speed of the other?

i think it isn't. what say?

30350
@dream_BLAC_2013 said:
I dont know if this post is gonna be sent as PG is repeatedly showing errors while posting Is there anything wrong? Y is this happening? Coming to the sum, I was getting the answer as only A, B will not be reqd as we have to find the total distance & NOT individual distances. But the answer key messes with my entire logic
some glitch is there in the answer as well as pg posting
30351
@DeAdLy U too think that the answer should be A ONLY, right? :O
30352
@dream_BLAC_2013 said:
@DeAdLy U too think that the answer should be A ONLY, right?
no i think both are required..because without knowing speed we cannot determine the point at which they meet the second time
30353
take A,speed 1 m/s and B's speed 50 m/s,then they wont have travelled 150 m to meet second time
30354
@dream_BLAC_2013 said:
@DeAdLy U too think that the answer should be A ONLY, right?
i think both are required because..because speed determines when their paths will overlap for second time
30355
@mailtoankit
bhai speed se farak padega yar..kitna distance those two cover
30356
@techgeek2050 said:
do u think this formula is valid when speed of one of them is greater that twice the speed of the other? i think it isn't. what say?
bhai solve this one using these formulas :

A person P is at X and another person Q is at Y.the distance between X and Y is 100km . speed of Q = 60km/hr
speed of P = 20km/hr

If they move to and fro b/w X and Y , what is the distance covered by Q, when they meet each other for the third time ?
ANS - 375 km
30357
@dream_BLAC_2013 said:
@DeAdLy U too think that the answer should be A ONLY, right?
my bad.... here both will be required. because 1st of all v need to know if the speed of one of them is greater than twice the speed of the other or not. bcz if it is, the 1 with greater speed will be completing more laps and thereby meeting the slower one multiple times. if it were greater v would have needed the actual speed to calculate the distance. since it isnt, v can find the distance

30358
@DeAdLy That is not reqd. Y do we need to determine how much distance EACH covers to meet for the 2nd time? 😲 We are asked to find ONLY the total distance covered (HOPEFULLY!!!)
30359
@dream_BLAC_2013 said:
@DeAdLy That is not reqd. Y do we need to determine how much distance EACH covers to meet for the 2nd time? We are asked to find ONLY the total distance covered (HOPEFULLY!!!)
total distance uptil which point or time..?? second time they meet right..
also where they meet second time it depends on their speed....
see above post 30306 by @shattereddream bhai
30360

The sides of a rectangular field of 726 sq m are in ratio 3:2, Find sides?
Ans is 33m & 22m. How?

30361
@amandeep2020 said:
The sides of a rectangular field of 726 sq m are in ratio 3:2, Find sides? Ans is 33m & 22m. How?
3x*2x = 726
x = 11
sides = 3*11,2*11 = 33,22
30362
y=1/3 +3/18+15/162+........... find the value of y^2+2y


30363
@DeAdLy Total distance covered till they meet for the 2nd time......For this, we dont need the speeds as total distance travelled when 2 ppl moving in opp direction meet for the 2nd time is 3*D. The same formula for 3rd meet is 5*D. So we really dont need the speed, do we? :O
30364
@dream_BLAC_2013 said:
@DeAdLy Total distance covered till they meet for the 2nd time......For this, we dont need the speeds as total distance travelled when 2 ppl moving in opp direction meet for the 2nd time is 3*D. The same formula for 3rd meet is 5*D. So we really dont need the speed, do we?
we do need the speed. bcz the formula will change depending on their relative direction.

30365
@techgeek2050 Actually its one of those which is independent of the direction. I wish I could show you how but cant do it online. But lets take the example of the sum posted in the last page for you (ans-375 wala sum). Lets solve it inside a minute using this shortcut-->

Total Distance travelled when they meet for the 3rd time- (5*100)km Relative speed- 60+20 = 80 km/hr
Time taken to meet for the 3rd time= D/S = 25/4 hrs
Distance travelled by Q in this time= 25/4 * 60 = 375 km

I understand the thing that u are trying to convey but it becomes too massive if we do sums like that, always trying to calculate whether they are in the same or opp direction. Use this formula for any similar sum & find out for urself :)
30366

Q. In the center of a square room with area 100 sq m, there is a square of turkey carpet, & the rest of the floor is covered with oil cloth. The carpet & the oil cloth costs respectively Rs 15 and Rs 6.50 per sq meter and the total cost of Carpet & oil cloth is Rs 1338.50. Find the width of oil cloth border.
Ans is - 1/2 metre. Please guys explain this.

30367
@bodhi_vriksha yaar kuch samajh me nai aaya..kaun sa method use kiya hai????....
30368
@techgeek2050 :s we get multiple values so the ans is cannot be determined ...my doubt is...hw did u calculate the value fr N2??