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:
119 comments Page 3 of 12.
Bhharath said:
6 years ago
Thanks @Abhishek.
Abhishek said:
6 years ago
A does the work in 23 days and he is 30% faster also, so B will do that work in (23+ 30% of 23)= 29.9 days.
Now work done in 1 day by A= (1/23) and B=(1/29.9),
work done by A+B in one day = (1/23 + 1/29.9) = 1/13,
So the workdone by A+B will be in 13 days.
Now work done in 1 day by A= (1/23) and B=(1/29.9),
work done by A+B in one day = (1/23 + 1/29.9) = 1/13,
So the workdone by A+B will be in 13 days.
(1)
Ajay said:
6 years ago
First, solve percentage i.e-30% = 3/10.
From that fraction, we can calculate the efficiency of both A and B which is 13 and 10.
Work=time x efficiency.
Total work =23x13
Time is taken by both to do the work=23x13/23,
=13 days.
From that fraction, we can calculate the efficiency of both A and B which is 13 and 10.
Work=time x efficiency.
Total work =23x13
Time is taken by both to do the work=23x13/23,
=13 days.
AMAN said:
6 years ago
The answer is approx 13 days.
As B would do the work in 230/7 days.
B's one day work would be 7/230.
a+b = x{1/23+7/230}=1.
x = apprx 13 days.
As B would do the work in 230/7 days.
B's one day work would be 7/230.
a+b = x{1/23+7/230}=1.
x = apprx 13 days.
BIKKU said:
7 years ago
a : B = 13 : 10,
13 * 23 = x * 23.
x = 13.
13 * 23 = x * 23.
x = 13.
Badal said:
7 years ago
E * d = w,
So, the Total work 13 * 23,
Together efficiency = 23.
So, (13 * 23)÷23 = 13 is the answer.
So, the Total work 13 * 23,
Together efficiency = 23.
So, (13 * 23)÷23 = 13 is the answer.
Thilagavathinagarajan said:
7 years ago
Why we consider 10:13::23:x? Please explain this step.
Divyanshu yadav said:
7 years ago
B's days to complete the work=days taken by A+30% of days taken by A.
= 23+ (30/100) *23= 29.9 days.
= 23+ (30/100) *23= 29.9 days.
Sonam said:
7 years ago
A=130 and B=100.
The efficiency A=13, B=10,
A=23 * 13,
A+B=23*13/23=13.
The efficiency A=13, B=10,
A=23 * 13,
A+B=23*13/23=13.
Aditya Ranjan said:
7 years ago
@All.
In this question you've shown B is 30% slower than A but the question is A is 30% faster so if B can finish the work in 100x days or let 100 days then A would do it in 70 days only. If there is not any mistake please make sure me where am I wrong.
In this question you've shown B is 30% slower than A but the question is A is 30% faster so if B can finish the work in 100x days or let 100 days then A would do it in 70 days only. If there is not any mistake please make sure me where am I wrong.
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