Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 26)
26.
A and B can do a work in 8 days, B and C can do the same work in 12 days. A, B and C together can finish it in 6 days. A and C together will do it in :
Answer: Option
Explanation:
| (A + B + C)'s 1 day's work = | 1 | ; |
| 6 |
| (A + B)'s 1 day's work = | 1 | ; |
| 8 |
| (B + C)'s 1 day's work = | 1 | . |
| 12 |
 (A + C)'s 1 day's work |
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So, A and C together will do the work in 8 days.
Discussion:
53 comments Page 5 of 6.
Husam said:
1 decade ago
One day's work for (A+B) is 1/8.
One day's work for (B+C) is 1/12.
One day's work for (A+C) is 1/X.
So,
(A+B)+(B+C)+(A+C) = 1/8+1/12+1/x.
2(A+B+C) = 1/8+1/12+1/x.
2*1/6 = 1/8+1/12+1/x.
1/x = 2*1/6-(1/8+1/12).
x = 1/8.
So,
One day's work for (A+C) = 1/8.
A and C finish work in 8 days.
One day's work for (B+C) is 1/12.
One day's work for (A+C) is 1/X.
So,
(A+B)+(B+C)+(A+C) = 1/8+1/12+1/x.
2(A+B+C) = 1/8+1/12+1/x.
2*1/6 = 1/8+1/12+1/x.
1/x = 2*1/6-(1/8+1/12).
x = 1/8.
So,
One day's work for (A+C) = 1/8.
A and C finish work in 8 days.
Nisha said:
1 decade ago
Why 2 is multiplied with 1/6.
To find out (A+C)'s work the equation is 2(A+B+C)-((A+B)+(B+C)).
On solving this equation,
A+B+C = 1/6;
A+B = 1/8;
B+C = 1/12;
(A+C)= 2(1/6)-(1/8+1/12),
= 1/8.
To find out (A+C)'s work the equation is 2(A+B+C)-((A+B)+(B+C)).
On solving this equation,
A+B+C = 1/6;
A+B = 1/8;
B+C = 1/12;
(A+C)= 2(1/6)-(1/8+1/12),
= 1/8.
Hussain said:
1 decade ago
Hey guys please say me.
How 1/12+1/24 = 1/8.
I did not understand the logic the lcm of these two numbers is 24.
How 1/12+1/24 = 1/8.
I did not understand the logic the lcm of these two numbers is 24.
Gregory wachiye said:
9 years ago
This is awesome. I have gained a lot with the help of this explanations.
Vick said:
1 decade ago
A's = (A+B+C) - (B+C) = 1/6-1/8 = 1/24.
B's = (A+b+C) - (A+B) 1/6-1/12 = 1/12.
A+C's (1/24) + (1/12) = 1/8.
Therefore they can complete in 8 days.
B's = (A+b+C) - (A+B) 1/6-1/12 = 1/12.
A+C's (1/24) + (1/12) = 1/8.
Therefore they can complete in 8 days.
Mukesh said:
1 decade ago
Any tell me how to solve this sum in L.C.M?
Jeeva909 said:
1 decade ago
Hi am little week in maths, so please somebody explain me the answer how this [2x1/6]-[1/8+1/12] came?
Y. Balaji said:
1 decade ago
@ Jeev.
Don't worry and don't confuse. Just think.
A+B+C = 1/6 => equation 1.
A+B = 1/8 => equation 2.
B+C = 1/12 => equation 3.
From equation 1&3 (1-3).
A = (1/6) - (1/12) = (1/12) => 4.
From equation 1&2 (1-2).
C = (1/6) - (1/8) = (1/24) => 5.
Now A+C = (1/12) + (1/24) = 1/8.
= 8 days.
Don't worry and don't confuse. Just think.
A+B+C = 1/6 => equation 1.
A+B = 1/8 => equation 2.
B+C = 1/12 => equation 3.
From equation 1&3 (1-3).
A = (1/6) - (1/12) = (1/12) => 4.
From equation 1&2 (1-2).
C = (1/6) - (1/8) = (1/24) => 5.
Now A+C = (1/12) + (1/24) = 1/8.
= 8 days.
Cheema said:
1 decade ago
How come 3/24?
Nandakumar said:
1 decade ago
How can i take 2*1/8-(1/8+1/12)?
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