Puzzles contest - 17 with answers

[HELP]

1. A railway track runs parallel to a road until a bend brings
the road to a level crossing. A cyclist rides along to work along the
road every day at a constant speed of 12 miles per hour. He normally
meets a train that travels in th'e same direction at the crossing. One
day he was late by 25 minutes and met the train 6 miles ahead of the level crossing. Can you figure out the speed of the train?



2. A friend of mine bought a used pressure cooker for Rs. 60. She somehow did not find it useful and so when a friend of hers offered her Rs. 70 she sold it to her. However, she felt bad after selling it and decided to buy it back from her friend by offering her Rs. 80. After having bought it once again she felt that she did not really need the cooker. So she sold it at the auction for Rs. 90.

How much profit did she make? Did she at all make any profit?





3. There is a number, the second digit of which is smaller than its first digit by 4, and if the number was divided by the digits'sum, the quotient would be 7 . Can you find the number?




4. A factory manufacturing flywheels for racing cars has tenachines
to make them. The manufacturer'knows the correct weight for a flywheel.
However, one day one of the, machine begins to
produce faulty parts-:-either overweight or under-weight. How can the manufacturer find the faulty machine in only two weighings





5. Recently I attended the twelfth wedding anniversary celebrations of my good friends Mohini and Jayant. Beaming with pride Jayant looked at his wife and commented, 'At the time when we got married Mohini was 3/4th of my age, but now she is only 5/6^th We began to wonder how old the couple mu31:have been at the time of their marriage! - Can you figure it out? from machine number two and so forth, and weigh these against the correct weight for that number of parts









Answers














1.
Let's assume that-the man and the train normally meet at the crossing at 8 AM..
then the usual time of.thecyclist
at the bend is 8 AM. and he is 6 miles behind at 7.30 AM. But when the cyclist
is late. he arrives at the
bend at 8.25 AM. and therefore he is six miles behind at 7.55 AM. Since the
train takes 5 minutes to


travel
the six mile run, the speed of the train is 72 m.p.h.


2. The woman made altogether
Rs. 20. She made Rs. 10 when she sold the item for tbe first time and another
Rs. 10 when she sold it for the second time.


3. The number is 84.




4
. The manufacturer must take one flywheel made by each
macliine, find their total weight and compare this with the weight of the
equivalent number of good flywheels to obtain the difference. Then,he must take 2
flywheel from machine number one, 2 flywheels from machine number two and so
forth and weigh there against the correct weight for that number of parts






5.
jayant was 24 and mohini was 18.42 While the first was,the example given, the top row must be
one of the four following numbers: 192.219.273 or
327.


















Edited by: HELP

[Dr YVS]

Qn2, treat it as 2 events


One purchase for 60 sell at 70


ecodn purchase for 80 and sell at 90

[Dr YVS]

Qn 5


LEy X, Y be rpesent ages


then 3/4(x-12) = y-12 and 5/6 x = y By solving


x=36 , y = 30

[muralisankars]

1. A railway track runs parallel to a road until a bend brings the road to a level crossing. A cyclist rides along to work along the road every day at a constant speed of 12 miles per hour. He normally meets a train that travels in th'e same direction at the crossing. One day he was late by 25 minutes and met the train 6 miles ahead of the level crossing. Can you figure out the speed of the train?

Ans:

Cyclist late by 25 min
remaining distance 6 miles
Cyclist Speed 12 miles per hour

So, Cyclist go to that crossing by 1/2 an hour (6/12).
The Time between today meeting point and normal meeting point=30min - 25min=5min

Therefore, the train reach that crossing point by 5 minutes.

So, The speed of the train is 72miles per hour

[ 6miles=5 mins
72miles=60mins]

[keerthi]

2. A friend of mine bought a used pressure cooker for Rs. 60. She somehow did not find it useful and so when a friend of hers offered her Rs. 70 she sold it to her. However, she felt bad after selling it and decided to buy it back from her friend by offering her Rs. 80. After having bought it once again she felt that she did not really need the cooker. So she sold it at the auction for Rs. 90.

How much profit did she make? Did she at all make any profit?


Ans)Profit = 20Rs


In the first sale she got 10Rs profit


In the second sale she got 10 Rs profit


total profit = 20Rs

[keerthi]

3. There is a number, the second digit of which is smaller than its first digit by 4, and if the number was divided by the digits'sum, the quotient would be 7 . Can you find the number?


Ans)84
let the no be xy , it can be written as 10x+y
given x-y = 4
and (10x+y)/(x+y) = 7
solving we get x=2y
so y =4 and x =8
Hence the number is 84

[keerthi]

3. Recently I attended the twelfth wedding anniversary celebrations of my good friends Mohini and Jayant. Beaming with pride Jayant looked at his wife and commented, 'At the time when we got married Mohini was 3/4th of my age, but now she is only 5/6th~ We began to wonder how old the couple mu.3t have been at the time of their marriage! . Can you figure it out?[/b]

Mohini =18yrs , Jayanth = 24yrs
Let the present ages be M and J and M=5/6(J)-----(1)
at the time of marriage M-12 = 3/4(J-12)----------(2)
Solving two equations(1) &(2)
we get M=30 and J=36
at the time of marriage their ages were = 30-12 =18 & 36-12 =24
M=18 and J=24

[keerthi]

1. A railway track runs parallel to a road until a bend brings the road to a level crossing. A cyclist rides along to work along the road every day at a constant speed of 12 miles per hour. He normally meets a train that travels in th'e same direction at the crossing. One day he was late by 25 minutes and met the train 6 miles ahead of the level crossing. Can you figure out the speed of the train?


Ans)speed of train is72 mph


lets consider they both meet daily at 9 am


As the man was late by 25 min he comes to meeting point at =9:25am


the speed of man = 12 mph


that means he takes 30min to cover 6 miles.


the man was 6 miles behind at = 8:55am


So in 5 minutes the train covered 6miles distance


Hence the speed of train = 60*6/5 = 72mph

[Ruchita Agarwal]

hi Keerthi,


I doubt for the answer u gave for 2 question,


i think he did not make any profit ,b'coz


at first sell he makes Rs. 10 profit but again when he purchased with Rs.80 he needs to add more Rs.10 to it so till here Rs. 10 loss ,


then he sells at Rs.90 with Rs.10 profit and with this Rs.10 he is able to clear loss from his previous purchase ,so no loss , no profit.

[sidhu]

hi friends , i don't have the knowledge on profit/loss chapter , but if i think in general way , i will say the answer for 2Que will be Rs.30 profit, because the lady purchase cooker at starting at 60 & sold at the end at 90, i m not considering the transaction in between them, if i m wrong,pls give me an exact answer by giving explanation

[keerthi]

hi ruchita and sidhu,


No confusions .


Assume that u bought two items one for 60 Rs and other for 80 Rs .


And assume that u sold them one for 70Rs and other for 90 Rs .


Profit is =20 Rs.


The only difference here is same object is bought and sold twice.


I Hope i am clear.If i am wrong let me know.


keerthi

[sidhu]

thanks keerthi ,


i got the point , thanks for that

[JotiN]

2) gprofit by 10 rupees
3)95
4) its mentioned in the Question itself
5) ages at marriage 24 and 18

JotiN [img]smileys/smiley1.gif[/img]