Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 17)
17.
A is 30% more efficient than B. How much time will they, working together, take to complete a job which A alone could have done in 23 days?
Answer: Option
Explanation:
Ratio of times taken by A and B = 100 : 130 = 10 : 13.
Suppose B takes x days to do the work.
Then, 10 : 13 :: 23 : x  x = |
 |
23 x 13 |  |
x = |
299 | . |
| 10 | 10 |
| A's 1 day's work = | 1 | ; |
| 23 |
| B's 1 day's work = | 10 | . |
| 299 |
| (A + B)'s 1 day's work = | |
1 | + | 10 | |
= | 23 | = | 1 | . |
| 23 | 299 | 299 | 13 |
Therefore, A and B together can complete the work in 13 days.
Discussion:
121 comments Page 13 of 13.
Dhiraj Bohara said:
1 month ago
Let X be the work efficiency of B.
According to the question, the efficiency of A becomes 1.3X,
Total efficiency of A and B = X+ 1.3X = 2.3X.
Therefore:
With 1.3X work efficiency, it takes 23 days.
With 2.3X (when A and B work together), it will take 23 × 1.3x/2.3x = 13 days.
According to the question, the efficiency of A becomes 1.3X,
Total efficiency of A and B = X+ 1.3X = 2.3X.
Therefore:
With 1.3X work efficiency, it takes 23 days.
With 2.3X (when A and B work together), it will take 23 × 1.3x/2.3x = 13 days.
(1)
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers