Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 8)
8.
A can do a certain work in the same time in which B and C together can do it. If A and B together could do it in 10 days and C alone in 50 days, then B alone could do it in:
Answer: Option
Explanation:
| (A + B)'s 1 day's work = | 1 |
| 10 |
| C's 1 day's work = | 1 |
| 50 |
| (A + B + C)'s 1 day's work = |  |
1 | + | 1 |  |
= | 6 | = | 3 | . .... (i) |
| 10 | 50 | 50 | 25 |
A's 1 day's work = (B + C)'s 1 day's work .... (ii)
| From (i) and (ii), we get: 2 x (A's 1 day's work) = | 3 |
| 25 |
 A's 1 day's work = |
3 | . |
| 50 |
 B's 1 day's work |
|
1 | - | 3 | |
= | 2 | = | 1 | . |
| 10 | 50 | 50 | 25 |
So, B alone could do the work in 25 days.
Discussion:
147 comments Page 9 of 15.
Anil said:
9 years ago
1/A + 1/B = 1/10 --->(1)
1/B + 1/C = 1/A --->(2)
C = 1/50 --->(3)
Just solve this three equation and you will get answer as B = 1/25.
1/B + 1/C = 1/A --->(2)
C = 1/50 --->(3)
Just solve this three equation and you will get answer as B = 1/25.
Imran said:
7 years ago
A+B=1/10. -----> (1)
A+B+C=(1/10 + 1/50) = 3/25.
A+A=3/25......(A = B+C).
A=3/50,
3/50 + B=1/10,
B=1/25,
B alone does it in 25 days.
A+B+C=(1/10 + 1/50) = 3/25.
A+A=3/25......(A = B+C).
A=3/50,
3/50 + B=1/10,
B=1/25,
B alone does it in 25 days.
Vikram sihag said:
1 decade ago
Efficency of a+b = 10%.
Efficency of c = 2%.
Efficency of a+b+c = 12%.
Put up a = b+c.
2(b+c) = 12%.
b = 4%
Days = 100/4 = 25.
Efficency of c = 2%.
Efficency of a+b+c = 12%.
Put up a = b+c.
2(b+c) = 12%.
b = 4%
Days = 100/4 = 25.
Pavan said:
7 years ago
A = B+C.
A+B = 1/10.
C = 1/50.
A+B+C = 6/50.
we know that A = B+C.
B+C+B+C = 6/50,
B = 1/25,
B takes 25 days to complete the work.
A+B = 1/10.
C = 1/50.
A+B+C = 6/50.
we know that A = B+C.
B+C+B+C = 6/50,
B = 1/25,
B takes 25 days to complete the work.
Sudip said:
2 years ago
Short and Simple:
a+b=10, c=50, total work 50.
perday a + b = 5, c = 1.
a+b = 5,
b+c+b = 5,
2b+c = 5,
b = 2/d.
b = 50/2 = 25.
a+b=10, c=50, total work 50.
perday a + b = 5, c = 1.
a+b = 5,
b+c+b = 5,
2b+c = 5,
b = 2/d.
b = 50/2 = 25.
(25)
Pavan@9966606261 said:
1 decade ago
A=B+C;
A+B=1/10;
A-B=1/50;
2A=1/10+1/50=6/50;
A=3/50;
A-B=1/50;
B=3/50-1/50;
B=1/25;
B ALONE CAN DO IN "25" DAYS
A+B=1/10;
A-B=1/50;
2A=1/10+1/50=6/50;
A=3/50;
A-B=1/50;
B=3/50-1/50;
B=1/25;
B ALONE CAN DO IN "25" DAYS
Shubham Uttam Bandgar said:
3 years ago
If A = B+C.
So A-B =C.
i,e A-B = 1/50 ----> eq 1
And
A+B = 1/10 ----> eq 2.
From eq 2 - eq 1 we will get the answer.
.
So A-B =C.
i,e A-B = 1/50 ----> eq 1
And
A+B = 1/10 ----> eq 2.
From eq 2 - eq 1 we will get the answer.
.
(25)
Neil said:
1 decade ago
A=B+C.
A+B+C = 1/10+1/50=6/50.
(B+C)+B+C = 2B+2C=6/50.
B+C = 6/100.
B = 6/100-1/50 = 1/25.
Therefore, B = 25 days.
A+B+C = 1/10+1/50=6/50.
(B+C)+B+C = 2B+2C=6/50.
B+C = 6/100.
B = 6/100-1/50 = 1/25.
Therefore, B = 25 days.
Sun said:
1 decade ago
A+b=10..2
c=1/50
sub (1) in (2)
2b+c=1/10
2b+1/50=1/10
2b=1/10-1/50
2b=5-1/50
2b=4/50
2b=2/25
b=25...
Hence proved
c=1/50
sub (1) in (2)
2b+c=1/10
2b+1/50=1/10
2b=1/10-1/50
2b=5-1/50
2b=4/50
2b=2/25
b=25...
Hence proved
Esayas said:
1 decade ago
If (a+b) = 1/10 and a = b+c, so 2b++c = 1/10.
2b+1/50 = 1/10.
b = 1/25.
So b can finish the work in 25 days.
2b+1/50 = 1/10.
b = 1/25.
So b can finish the work in 25 days.
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