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 11 of 12.
Ved Prakash Singh said:
8 years ago
B can Complete the work in:
(A's)70 days means (B's)100 days.
(A's)23 days means (B's)100/70*23,
so, x/23+70x/100*23=1.
x=13days ans.
(A's)70 days means (B's)100 days.
(A's)23 days means (B's)100/70*23,
so, x/23+70x/100*23=1.
x=13days ans.
Ab Siddique said:
8 years ago
Here, A's efficiency : B's efficiency = 130:100.
So , A time: B time=100:130 or 10:13.
Now we calculate this,
If A takes 10 days B takes = 13 dyas.
If A takes 1 days B takes = 13/10 days.
If A takes 23 days B takes = (13*23)/10 days =299/10.
So B's 1 day work=10/299 and A's 1 day work=1/23.
So A and B work together = 1/23+299/10 = 1/13.
So total time required to finish this job together = 13 days.
So, answer is 13.
So , A time: B time=100:130 or 10:13.
Now we calculate this,
If A takes 10 days B takes = 13 dyas.
If A takes 1 days B takes = 13/10 days.
If A takes 23 days B takes = (13*23)/10 days =299/10.
So B's 1 day work=10/299 and A's 1 day work=1/23.
So A and B work together = 1/23+299/10 = 1/13.
So total time required to finish this job together = 13 days.
So, answer is 13.
Tom cruz said:
8 years ago
A's efficiency = 100/23 = 4.35;
since A is 30% more efficient than B:
A = 30%B + B or A = 1.3B or B = A/1.3;
then B = 4.35/1.3 = 3.35;
then, working together;
4.35 + 3.35 = 7.7;
100/7.7 = 12.98 or 13 days.
since A is 30% more efficient than B:
A = 30%B + B or A = 1.3B or B = A/1.3;
then B = 4.35/1.3 = 3.35;
then, working together;
4.35 + 3.35 = 7.7;
100/7.7 = 12.98 or 13 days.
Am average said:
7 years ago
A' 1day work =1/23,
A/c question,A is 30% more efficient than B.
i.e; A = 30% of B so;
1/23= 130/100 *B.
10/299=B 's 1-day work.
Note: when X % more is given, you have to take 100+x, if says X % less, then have to take
100-x.
So, (A +B ) 1 'days work = 1/23+10/229,
= 1/13.
Whole work to complete by A+B takes 13days.
A/c question,A is 30% more efficient than B.
i.e; A = 30% of B so;
1/23= 130/100 *B.
10/299=B 's 1-day work.
Note: when X % more is given, you have to take 100+x, if says X % less, then have to take
100-x.
So, (A +B ) 1 'days work = 1/23+10/229,
= 1/13.
Whole work to complete by A+B takes 13days.
Deepanshu yadav said:
7 years ago
A's 1 day work=1/23.
B's 1 day work=1/23(70/100)=7/230, since B is 30 % less efficient than A.
( A+B )'s 1day work = 1/23 +7/230 = 17/230.
So both can do the work in 230/17 days = 13.529 days.
Is it correct or not?
Can anyone tell me? Please.
B's 1 day work=1/23(70/100)=7/230, since B is 30 % less efficient than A.
( A+B )'s 1day work = 1/23 +7/230 = 17/230.
So both can do the work in 230/17 days = 13.529 days.
Is it correct or not?
Can anyone tell me? Please.
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.
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.
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.
Thilagavathinagarajan said:
7 years ago
Why we consider 10:13::23:x? Please explain this step.
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.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers