IBM
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Numerical Ability
Time and Work
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?
Read Solution (Total 7)
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- 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.
- 8 years agoHelpfull: Yes(20) No(0)
- 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 - 8 years agoHelpfull: Yes(5) No(0)
- 5/3 hours is the right answer
- 8 years agoHelpfull: Yes(3) No(0)
- 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 - 8 years agoHelpfull: Yes(2) No(0)
- 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. - 8 years agoHelpfull: Yes(1) No(13)
- 23/15 hours. as the amount of work done is 3/4 by c in 4.5 hours
- 8 years agoHelpfull: Yes(0) No(15)
- my answer is 3 and half hours
- 5 years agoHelpfull: Yes(0) No(0)
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