Aptitude - Time and Work - Discussion

Discussion Forum : Time and Work - General Questions (Q.No. 20)
20.
Sakshi can do a piece of work in 20 days. Tanya is 25% more efficient than Sakshi. The number of days taken by Tanya to do the same piece of work is:
15
16
18
25
Answer: Option
Explanation:

Ratio of times taken by Sakshi and Tanya = 125 : 100 = 5 : 4.

Suppose Tanya takes x days to do the work.

5 : 4 :: 20 : x    x = 4 x 20
5

x = 16 days.

Hence, Tanya takes 16 days to complete the work.

Discussion:
94 comments Page 1 of 10.

Kamlesh jaiswal said:   1 decade ago
The given answer is correct.

Sakshi's one day work=1/20
Tanya's one day work =(1/20 + 25% of 1/20) = 1/20+1/80 = 1/16.

So Tanya can complete the work in 16 days.
(1)

Siddharth said:   1 decade ago
Thanks kamal you are right.

Sandeep said:   1 decade ago
If tanya is 25% more efficient than sakshi (whic means tanya>sakshi) then how cum the ratio between sakshi n tanya is 125:100 it should be 100:125 right?.

Sujith said:   1 decade ago
Tanya is 25% more efficient than Sakshi. Then ratio should be 3:4 rite ?.

Sundar said:   1 decade ago
@Sujith and @Sandeep

You are wrong.

The given ratio is about "TIME TAKEN" not the ratio of work done.

If Tanya is more efficient (25%) than Sakshi - means Tanya will take less time than Sakshi to complete the work.

We can say the same thing in another way, i.e., Sakshi is 25% INEFFICIENT than Tanya. So, if Tanya takes 100 hours to complete a task then Sakshi will take 125 hours (25% extra than Tanya) to complete the same task.

So, time taken by
Tanya = 100 hours ,
Sakshi = 125 hours.

Therefore, Ratio of times taken by Sakshi and Tanya = 125 : 100 = 5 : 4.

This is what the first line in the given explanation.

Hope this will help you. Have a nice day!

Kiran Joy said:   1 decade ago
Can't we take time taken by tanya and sakshi as 75:100.

Deepti said:   1 decade ago
Thanks sundar that solves so many other related problems.

Chandu said:   1 decade ago
5 : 4 :: 20 : x

Can you explain the meaning of the above line?

Vamshidhar reddy said:   1 decade ago
25% efficient(so one takes 100 days means second person takes 75days[just 75%of 100])

here one takes 20 days
so other takes 20*(75/100)=15 days

Preethy said:   1 decade ago
I too get the answer as 15 days. Since 25% of 20 is 5 we have to subtract like 20-5=15 rite? but how the answer is 16?


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