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?
11 days
13 days

20 3 days
17

None of these
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 4 of 12.

Dawood Sheriff said:   1 decade ago
Actually A is more efficient than B as per the question,
Then A could be 130% of B.

B = 10/13*23=230/13.
A = 1/23 ,for a day.

B = 230/13, for a day.
Therefore (A + B)T = 1.
(13/230 + 1/23)T = 1.
T = 10.

Amrith said:   1 decade ago
@shakthi.

Then A's efficiency(A/C to question) = x+x*(30/100) = 13x/10....(2).

They are telling that a is 30% more efficient than b right. So it will be A=30/100 + x right....why x is multiplies with 30/100.

Swati said:   1 decade ago
Let no of days taken by A = x and by B = y.

Then, (y-x)/y = 30/100.
Gives x:y = 7:10.
Not 10:13.

Please help me in this.

Ramesh said:   1 decade ago
Why should we use the days as A = 100 and B = 130? Cant we use it as A = 30 and B = 60?

Shiva said:   1 decade ago
23 days------------>130%.

? days------------->230%.

130/230*23 = 13 days.

Ammulu ch said:   1 decade ago
How 230%? Please explain clearly.

Jeetu said:   1 decade ago
I agree with Shahid basha.

According to the language used in the above question base should be B's efficiency and not A's because in the given explanation to the question 100 is 76% approx of 130 and not 70% (100%-30%) as required.

Pallavi said:   1 decade ago
A person can do 1/6th of the work in 2 days. If he now works 50% faster, in how many days can he finish the remaining work ?

Rahul said:   1 decade ago
@Pallavi.

He will complete his remaining work in 5 days.

Umesh said:   1 decade ago
@Rahul.

How in 5 days please explain?


Post your comments here:

Your comments will be displayed after verification.