Aptitude - Time and Work - Discussion

According to me, it should be;

Tanya is 25% efficient than Sakshi so that means she finishes work taking 25% less time.

So, 20 - 25 * 20, then finally we get 15 days.

Hi friends I agree your answer is 16 based on your methods.

So please let me know how many days Tanya takes if she is 50% more efficient than sakshi based on your methods.

What if I think tanaya takes 75 days and sakshi takes 100 days, then answer will be 15 days.

Sakshi do 1 day's the work = 1/20.

Now, Tanya do the work 25% more efficient than Sakshi = 1/20*25/100 = 1/80.

So, Tanya will do the total work = 1/20+1/80 = 5/80 = 1/16.

So 1*16/1 = 16 days.

Sakshi does 1 unit in =20Days.

Tanya does (1+1/4)=5/4 unit in = 20Days.
So, Tanya does one unit in=20*4/5 = 16 days,
I think efficiency here is related to the amount of work done.

@All.

The sentence 'Tanya is 25% more efficient than Sakshi' means Tanya will take 25% less days than Sakshi and not that Sakshi will take 25% more days than Tanya. The answer given assumes the later part which is not correct. Percents work differently for the increase and decrease.

For example, 25% more than 100 is 125. But 25% less than 125 is not a hundred.

The answer would be 16 if the question had been stated as Sakshi is 25% less efficient than Tanya.

[Tanya effective than sakshi [20days] , hence answer should be less than 20days]

Sakshi 125--------->20
Tanya 100-------->?
[cross multiply]
20 x 100 / 125 =16days.

Sakshi cannot be taken as 125, as Sakshi is the reference point here, she must be taken as 100.

So, Tanya becomes 75 (25% more efficient).
Then the ratio becomes 4:3 instated of 5:4.

25% of 20 is 5 then the answer is 20-5=15. But how it is 16?

Sakshi efficiency is 1/20.
Tanya Efficiency is 25% more than Sakshi.
So, 1/20+(25%of1/20)=16%.