Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 24)
24.
A works twice as fast as B. If B can complete a work in 12 days independently, the number of days in which A and B can together finish the work in :
Answer: Option
Explanation:
Ratio of rates of working of A and B = 2 : 1.
So, ratio of times taken = 1 : 2.
| B's 1 day's work = | 1 | . |
| 12 |
 A's 1 day's work = |
1 | ; (2 times of B's work) |
| 6 |
| (A + B)'s 1 day's work = |  |
1 | + | 1 |  |
= | 3 | = | 1 | . |
| 6 | 12 | 12 | 4 |
So, A and B together can finish the work in 4 days.
Discussion:
29 comments Page 1 of 3.
Pedada PavanGovind said:
3 years ago
A:B is 24:12 = 1:2 =>3 total efficiency.
Given B complete in 12 days.
Then together work in 12/3 = 4 days.
Given B complete in 12 days.
Then together work in 12/3 = 4 days.
(7)
Aditya said:
4 years ago
A finished work in 6 days.
B finishes work in 12 days.
Calculating LCM we get 12 which is total work.
Now, work efficiency of A = 12/6 = 2 unit/day,
work efficiency of B = 12/12 = 1 unit/day,
working together A+B = 2+1 = 3unit/day,
Therefore for finishing 12 unit work together they need 12/3 = 4 days.
B finishes work in 12 days.
Calculating LCM we get 12 which is total work.
Now, work efficiency of A = 12/6 = 2 unit/day,
work efficiency of B = 12/12 = 1 unit/day,
working together A+B = 2+1 = 3unit/day,
Therefore for finishing 12 unit work together they need 12/3 = 4 days.
(6)
Roy said:
5 years ago
@All.
Given A=2B.
B's 1 day work = 1/12,
So A's 1 day work=2*1/12=1/6.
(a+b)1 day = 1/6 + 1/12 = 1/4,
Hence 4 days.
Given A=2B.
B's 1 day work = 1/12,
So A's 1 day work=2*1/12=1/6.
(a+b)1 day = 1/6 + 1/12 = 1/4,
Hence 4 days.
(3)
Karthick M said:
4 years ago
Easiest method to solve this type of problem..
Given. A=2B.
(A+B)'s 1day work = 1/12=(2B+B)'s 1day work
3B's 1day work =1/12.
B's 1-day work =1/4.
So, B's whole work done is 4 days.
Given. A=2B.
(A+B)'s 1day work = 1/12=(2B+B)'s 1day work
3B's 1day work =1/12.
B's 1-day work =1/4.
So, B's whole work done is 4 days.
(1)
Uma said:
6 years ago
A=x, B = 2x.
1/x+1/2x = 1/12,
3/2x = 1/12,
3/6 = 2, x = 2.
so, B = 2x, 2 * 2 = 4.
1/x+1/2x = 1/12,
3/2x = 1/12,
3/6 = 2, x = 2.
so, B = 2x, 2 * 2 = 4.
(1)
Aravind_appu said:
1 decade ago
A = 2b------(1).
B = 1/12------(2).
1 sub in 2.
A = 2(1/12).
A = 1/6.
Total work is done TH = A+B.
TH = (1/6+1/12).
= (12+6)/(6*12).
= (18/72).
= 1/4.
= 4 day exactly.
B = 1/12------(2).
1 sub in 2.
A = 2(1/12).
A = 1/6.
Total work is done TH = A+B.
TH = (1/6+1/12).
= (12+6)/(6*12).
= (18/72).
= 1/4.
= 4 day exactly.
(1)
Deepa said:
1 decade ago
A:B = 1:2.
B can complete a work in 12 days.
Let A can complete in X days.
X:12 = 1:2.
X = 1*12/2.
X = 6 i.e, A = 6.
(A+B) 1 day work = 1/6+1/12 = 1/4.
So, A and B finish work in 4 days.
B can complete a work in 12 days.
Let A can complete in X days.
X:12 = 1:2.
X = 1*12/2.
X = 6 i.e, A = 6.
(A+B) 1 day work = 1/6+1/12 = 1/4.
So, A and B finish work in 4 days.
(1)
Rajat pundir said:
8 years ago
a/b=2/1.
Now using the ratio method.
1/12=1/3*(a+b).
1/4=a+b.
Hence 4 days.
Now using the ratio method.
1/12=1/3*(a+b).
1/4=a+b.
Hence 4 days.
(1)
Amrit said:
8 years ago
suppose B =x;
and A works twice =2x,
then the total amount of work is;
2x+x=12;
3x=12,
x = 4.
and A works twice =2x,
then the total amount of work is;
2x+x=12;
3x=12,
x = 4.
(1)
Sudhanshu said:
10 years ago
T --------- W
B --------- 1 1/12
A ---------1 1/6
If A+B work
W --------- T( days)
1/4 --------- 1/1/4.
It comes 4days.
B --------- 1 1/12
A ---------1 1/6
If A+B work
W --------- T( days)
1/4 --------- 1/1/4.
It comes 4days.
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