Latest TCS Aptitude Question SOLUTION:  A completes 80% of a work in 20 days. Then B also joins and A and B together finish the remaining work in 3 days. How long does it need for B if h

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(#M40115759) TCS Numerical Ability question time and work Keep an EYE

 A completes 80% of a work in 20 days. Then B also joins and A and B together finish the remaining work in 3 days. How long does it need for B if he alone completes the work?

Asked In TCS harish (9 years ago)

Unsolved Read Solution (9)

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Read Solution (9) :

Vinod chauhan  (9 years ago)

A completes 4/5 work in 20 days
so he can complete the whole work in (5*20)/4 = 25 days
A one day work is 1/25 ------ (1)
A & B Complete the 1/5 of work in 3 days
They Both can complete the work in 5*3 = 15 days
One day work of A nd B is 1/15 ----- (2)
B one day work is 1/x;
1/x= 1/15-1/25
1/x = 2/75
x = 75/2 ==>> 37.5
b can complete whole work in 37(1/2) days

Is this solution Helpfull? Yes (32) | No   

chandan goswami  (9 years ago)

Efficiency of A=80/20=4%
Efficiency of A+B=20/3=6.66%
so,
Efficiency of B=6.66-4=2.66
No of days need by B to complete the work alone=100/2.66=37.59
=38 days approx

Is this solution Helpfull? Yes (14) | No (1)  

B.Vinodkumar  (8 years ago)

For all friends..
work = days

for A:
80% work = 20 days
4/5 work = 20 days
cross mul
1 work = 5/4 * 20 days
1 work = 25 days
A's 25 days = 1 work ----------------------------->1

A+B remain work done in 3 days
total work = 1
80% work = 4/5
100% work = 1
100% - 80% = 1 - 4/5 = 1/5

for A+B:
work = days
1/5 work = 3 days
cross mul
1 work = 15 days
dat is

A+B's 15 days = 1 work --------------------------->2

now we know A's and A+B's work
now find B's work
apply A's in A+B's
A+B 1 Days= 1/15 works
A's 1 days = 1/25 works---->from 1..

1/25 + B = 1/15 works
B's days = 1/15 - 1/25 Works
B's days= 2/75 works
we have to calc works
cross mul
B's work = 75/2 days = 37 1/2 days
Rahul said: (Sat, Jan 29, 2011 08:45:53 AM)

@ baskar: thanks dude
Rajendra said: (Tue, Feb 8, 2011 01:54:11 AM)

A does 80% in 20 days..so
A does 100% in 25 days..
A's 1 day work=1/25
A+B does 20% in 3 days..so
A+B does 100% in 15 days
A+B's 1 day work=1/15
1/25+B=1/15
B=1/15-1/25
B,s 1 day work=2/75
so B,s work=75/2 i.e 37 1/2 days..

Is this solution Helpfull? Yes (2) | No   

Shreya Singh  (9 years ago)

B completes the work in 37.5 days

Is this solution Helpfull? Yes (1) | No   

ankur  (9 years ago)

100% done in 25 days by A .
and 100% done in 15 days by B.
so 5-5/3=37.5

Is this solution Helpfull? Yes | No (1)  

Shreya Maiwal  (9 years ago)

B alone do the work in xy/x-y days
15*25/10=37.5 days

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jyoti verma  (8 years ago)

15/22 b alone can do it

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tanvi saxena  (8 years ago)

since A can do 80% work in 20 days
then in 1 day it can do work= 80%/20=4/100
let B in 1 day ,work=1/x
so we can say,
20(4/100)+3(4/100 + 1/x)=1
4/5+12/100+3/x=1
x=37.5
thus ,B takes 37.5 days

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Ashish Aggarwal  (8 years ago)

37.5 days is answer

23/25 +3/x =1


x=37.5

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