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:
353 comments Page 5 of 36.
VisHnu RaM said:
4 years ago
Thank you for giving the clear explanation @Swetha.
And 60 will come, No of days LCM
15 days to 15 * 4 = 60.
20 days to 20 * 3 = 60.
So, the LCM is 60.
And 60 will come, No of days LCM
15 days to 15 * 4 = 60.
20 days to 20 * 3 = 60.
So, the LCM is 60.
(13)
Bhawana said:
7 months ago
Please explain me about the remaining work.
(12)
Syam said:
1 year ago
@Sree.
15 is written as = 5 * 3 and 20 is written as 2^2 *5 then 5 is the common then from 15 take 3 and 20 take 2 square, then 4*3*5=60 then 1 * 4/15 * 4 = 4/60 and for 1/20 =1 * 3/20 * 3 = 3/60.
Then the final answer is 4/60 + 3/60 = 7/60.
15 is written as = 5 * 3 and 20 is written as 2^2 *5 then 5 is the common then from 15 take 3 and 20 take 2 square, then 4*3*5=60 then 1 * 4/15 * 4 = 4/60 and for 1/20 =1 * 3/20 * 3 = 3/60.
Then the final answer is 4/60 + 3/60 = 7/60.
(11)
Mish said:
3 years ago
@All.
Why (A+B)'s 4 days of work is calculated?
Why it's not 3,5,6,7 or any other day?
What is the logic behind it?
Why (A+B)'s 4 days of work is calculated?
Why it's not 3,5,6,7 or any other day?
What is the logic behind it?
(10)
Sugan said:
2 years 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.
(8)
Kalai said:
2 years ago
How remaining work =1? Please explain to me.
(7)
SAKSHI said:
3 months ago
Yes, It is 8/15.
(7)
Swetha said:
4 years ago
First of all, thank you to explain the method.
I have a doubt that how we know to take (i.e Total work = 60)?
Anyone, please help me to get it.
I have a doubt that how we know to take (i.e Total work = 60)?
Anyone, please help me to get it.
(6)
Sivagami said:
2 years ago
How 7/60 came? Please explain.
(6)
Guna said:
1 year ago
Agree, the answer is D.
(6)
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