Latest IBM Aptitude Question SOLUTION: to do certain work alone 'A' takes 4 hrs,'B' takes 5 hrs and c takes 6 hrs.how long would A and b together take to do a work which C can do in 4 n half hours?

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to do certain work alone 'A' takes 4 hrs,'B' takes 5 hrs and c takes 6 hrs.how long would A and b together take to do a work which C can do in 4 n half hours?

Asked In IBM Samjukta Das (8 years ago)

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Read Solution (7) :

sarbasis das  (8 years ago)

A and B together does 9/20th of the work in an hour. C alone does 1/6th of the work in an hour. so in 4.5 hours C does 4.5/6th of the work. time required for A and B to do the same work is {(4.5/6)/(20/9)}=5/3hours.

Is this solution Helpfull? Yes (20) | No   

Rishi Kaul  (8 years ago)

RATE * TIME = WORK
A 30 4 120
B 24 5 120
C 20 6 120

AS L.C.M OF 4,5,6 is 120 rates can be found out easily
now
c's 4.5 hrs of work = (A+B)'s of work
20*2.5=(30+24)*Time (r*t=w)
Time taken by A & B =5/3 hrs

Is this solution Helpfull? Yes (5) | No   

banny  (8 years ago)

5/3 hours is the right answer

Is this solution Helpfull? Yes (3) | No   

mahesh lekurwale  (8 years ago)

C do the work in 4.5/6 hrs = 3/4 (Total work)
A do that work in 3/4 * 4 = 3
B do that work in 3/4 * 5 = 3.75
Therefore A and B do the work in x/ 3 + x / 3.75 = 1
x = 1 2/3 hrs

Is this solution Helpfull? Yes (2) | No   

vivek sharma  (8 years ago)

A's one hour Work=1/4
B's one hour work=1/5
C's one hour work=1/6
let us consider A and B together work by x hours
so
(x/4)+(x/5)+(9/2*6)=1
x=5/9
so total time taken by A & B is 9/5.

Is this solution Helpfull? Yes (1) | No (13)  

Debamalya Dawn  (8 years ago)

23/15 hours. as the amount of work done is 3/4 by c in 4.5 hours

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ANANYA BIHARI  (5 years ago)

my answer is 3 and half hours

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