Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 1)
1.
A can do a work in 15 days and B in 20 days. If they work on it together for 4 days, then the fraction of the work that is left is :
Answer: Option
Explanation:
| A's 1 day's work = | 1 | ; |
| 15 |
| B's 1 day's work = | 1 | ; |
| 20 |
| (A + B)'s 1 day's work = |  |
1 | + | 1 |  |
= | 7 | . |
| 15 | 20 | 60 |
| (A + B)'s 4 day's work = | |
7 | x 4 | |
= | 7 | . |
| 60 | 15 |
| Therefore, Remaining work = | |
1 - | 7 | |
= | 8 | . |
| 15 | 15 |
Discussion:
344 comments Page 2 of 35.
Hari said:
11 months ago
@Vishnu.
Can you explain the process in detail please?
Can you explain the process in detail please?
(14)
Vishnu said:
12 months ago
A->15.
B->20.
LCM of 15,20 is 60.
A can do 4 parts and B can do 3 parts.
A and B together complete 7 parts in 1 day.
for 4 days 28 parts can complete.
60-28 = 32(leftover work).
32/60 = 8/15.
B->20.
LCM of 15,20 is 60.
A can do 4 parts and B can do 3 parts.
A and B together complete 7 parts in 1 day.
for 4 days 28 parts can complete.
60-28 = 32(leftover work).
32/60 = 8/15.
(268)
Bha said:
12 months ago
Thanks all for explaining the answer.
(23)
Anonym said:
1 year ago
A, completes the work in 15 days so, the work done by A in 1 day = 1/15.
Similarly, B completes the work in 20 days therefore work done by B in 1 day = 1/20.
A and b work together = 1/15+1/20 i.e. => 14/120 => 7/60.
Now, they both worked for 4 days which will be = 4*7/60 => 7/15.
Let's suppose the total work is x and they have already worked for 4 days.
Therefore remaining work is x -7/15 (for more clarity take x-7/15 = 0) => 8/15.
Similarly, B completes the work in 20 days therefore work done by B in 1 day = 1/20.
A and b work together = 1/15+1/20 i.e. => 14/120 => 7/60.
Now, they both worked for 4 days which will be = 4*7/60 => 7/15.
Let's suppose the total work is x and they have already worked for 4 days.
Therefore remaining work is x -7/15 (for more clarity take x-7/15 = 0) => 8/15.
(25)
John michael said:
1 year ago
15 + 20 = 35,
15 * 20 = 300,
35/300 = 7/60.
15 * 20 = 300,
35/300 = 7/60.
(34)
Nitika said:
1 year ago
The reason why we've subtract from 1:
1 represents the whole work or complete work total work considered as 1(or 100%)
1 represents the whole work or complete work total work considered as 1(or 100%)
(23)
Sugan said:
1 year ago
1 (total work) - 7/15 (together completed work in 4 days).
Lcm = 15 then (15/15 -7/15) = 8/15.
Lcm = 15 then (15/15 -7/15) = 8/15.
(7)
Rakesh said:
1 year ago
1/15+1/20 LCM of this is 60.
So,
(1/15 * 60 + 1/20 * 60)/60we can simplify this you can get (4+3)/60 = 7/60.
So,
(1/15 * 60 + 1/20 * 60)/60we can simplify this you can get (4+3)/60 = 7/60.
(3)
Ashim said:
1 year ago
How 7/60 came? Anyone, please explain to me.
(14)
Sivagami said:
1 year ago
How 7/60 came? Please explain.
(6)
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