Time speed, work, Alligations and mixtures problems

[madhavi]

On 24th day B will complete the work in C-A-B order. right??
then 25th day it will be C's turn again.isin't?? How can be it be A's turn??

Originally Posted by rajsher

If we take this question as it is then answer is---

Day 1 - 0
next three days 1/10 + 1/15 - 1/20 = 7/60

so till 25 days work done is 56/60 and work left is 1/15

so the next day A will finish in (1/15)/(1/10) = 2/3 days

So answer 25 2/3 days

[estranged_gnrs]

Originally Posted by eagles_dare13

without multiplying actually, is there a way to tell which is greater ..
say 61*94 and 92 * 65.
This comes in handy in DI.
Also , please tell me exactly how remebering reciprocals upto 30 will fhelp.
becasue i can calculate percentages by adjusting numerator and denominator until the denom is 100.

the shortest approach i can think of is like,comparing the digits at tenth place,both are same.but 61*4 = 244 and 65*2 = 130 ..so can say first is greater.

recirpocals help u in many ways.at least upto 12 is important.adjusting the fraction will take more time.but suppose u have the follwoing fractions,
4/7,5/8,7/12 and u have to sort them...

4/7 is aprrox 57%(14% *4)
5/8 is 62.5% (12.5 % *5)
7/12 is 58.33%( 8.33% * 7)

so it helps if u know if 1/12 = 8.33% etc etc etc ..saves time...

Rohit

[rajsher]

Originally Posted by Zorro

In 3 days..work done = 7/60.

The Catch: C Starts with Zero work.. so he has nothing to demolish.
so in day 1 C does Zero Work. so the Patter is ABC..ABC....

In 24 days.. work done = 56/60...
so work left is 1/15. and days passed is 25.

Time taken by a to complete 1/15 th of work is 10/15 = 2/3

ie 252/3 days... pls correct me


1/15...

Me corrected zorro bhai

Avatar me Mask of zorro ki photu lagaooge to achha lagega

cheers,
Rajsher

[rajsher]

Originally Posted by madhavi

On 24th day B will complete the work in C-A-B order. right??
then 25th day it will be C's turn again.isin't?? How can be it be A's turn??

See the post by zorro.....

We have changed the pattern from CAB CAB CAB to
C ABC ABC ABC

and that is the only reason why we r calculating number of days as 1 + 3 + 3 + 3..
So after 1 + 24 days i.e. after 25 days, we r finished till ABC.
So the next day, it is A's turn.

cheers,
Rajsher

[MrAnderson]

Originally Posted by eagles_dare13

without multiplying actually, is there a way to tell which is greater ..
say 61*94 and 92 * 65.
This comes in handy in DI.
Also , please tell me exactly how remebering reciprocals upto 30 will fhelp.
becasue i can calculate percentages by adjusting numerator and denominator until the denom is 100.

61* 94 and 92 * 65 ..
y dont u compare ..61/65 and 92/94
61/65 is 1-(4/65) and the other is 1- (2/94)
clearly... 92/94 is bigger => 92 * 65 is greater..
cos if a/b > c/d then ad > bc...
just a thot...
andy.

[c21]

exactly the answer is 24 2/3 days

[Zorro]

I couldnt get you ....
instead of considering 61*4 and 65*2 in 61*94 and 92 * 65

why not consider 94*1 = 94 and 92*5 =460 ... and say 2 is greater
Can you pls elucidate?

Originally Posted by estranged_gnrs

the shortest approach i can think of is like,comparing the digits at tenth place,both are same.but 61*4 = 244 and 65*2 = 130 ..so can say first is greater.

recirpocals help u in many ways.at least upto 12 is important.adjusting the fraction will take more time.but suppose u have the follwoing fractions,
4/7,5/8,7/12 and u have to sort them...

4/7 is aprrox 57%(14% *4)
5/8 is 62.5% (12.5 % *5)
7/12 is 58.33%( 8.33% * 7)

so it helps if u know if 1/12 = 8.33% etc etc etc ..saves time...

Rohit

[estranged_gnrs]

Originally Posted by Zorro

I couldnt get you ....
instead of considering 61*4 and 65*2 in 61*94 and 92 * 65

why not consider 94*1 = 94 and 92*5 =460 ... and say 2 is greater
Can you pls elucidate?

no harm in thinkin as 94*1 instead of 61*4 ,but i will say 65*2 is easier to calculate in mind than 92*5....its ok yaar..just hw u see it and with wat ever u r comfy.
i just putin my 2 cents.
Rohit.

[mr_quipster]

i quite like this idea..posting questions online and solving real time. keeps the flow going in office too
i dunno if there is any other thread for doing this. if not, how bout posting questions from any topic and solving real time?

[mr_quipster]

Take a jab at this one


Which is the smallest number consisting only of 0s and 1s which is divisible by both 9 and 25?