Aptitude - Time and Work - Discussion

I am not getting it how 16?

Let's think this way Sakshi take 20 days which is 240 hours.
25% of 240 = 60.
240 - 60 = 180.
and 180 hours = 15days.

Please can anyone help me.

See This for those Who do Time and work with LCM..

It is said that Sakshi can do a piece of work in 20 days with her efficiency so we cannot take 25%of 20.

Here it is given 25% more efficient.
So efficiency of Sakhsi : Tanya.

Assume: S:T = 100unit : 125 unit (25%more).

Therefore ,
Total work = 100unit x 20days.
:. Tanya would do the same work in:
Total work/ Tanya efficiency,
:. 100unit x 20/125= 16 days.

Why not 15 days? Explain..
100%=20 day.
25%=x day.
X = 5 days.

Now take efficient that we need to subtract 20-5 = 15 days.
Explain to me if I am wrong.

Sakshi complete the work in 20 days . Tanya is 25% more efficient means;
in 20days 25%=5 days.
it means t complete the work in 5 days earlier.
so 20-5=15 answer.

Then how it comes as 16?

@All.

Tania is 25% more efficient then Sakshi so we can do it like,
Tania=125 units/day, Sakhi = 100 units/day.
As Sakhi done it in 20 days so we can find complete work done,
Total work= 20 * 100 = 2000.

We also have Tania unit work so we will divide total work with Tania unit work,
Tania work= 2000/125 = 16 answer.

A certain number of men do a piece of work in 10 days, if there are 10 men less, it will take 10 days more to finish the work. How many men were there originally. Can anyone solve this to find a solution?

Here (125% of 1/20)=1/16 that means in 16 days.

@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.

Can anyone please compare it with the 17th question?

@Ashan Naveed.

Consider 100 unit by Sakshi
Tanya 125 unit. Y can't we consider Sakshi by 125 days. Tanya in 100 days. Mainly unitary method how can we solve.