Aptitude - Time and Work - Discussion

@Sakshi.

If takes 125 times to complete her work in 20 days, Tanya takes 100.

Therefore if we cross multiply to find how much days will Tanya take to complete work.

i.e 125/100*20/? we get 16!

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.

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 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?

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.

Let us solve this easily.

Tanya : Sakshi
x : 20.
100 : 125.

Cross multiplication:
x = 100 * 20/125 = 16 days.

@Vamshidar reddy, Preethy& Samar;.

The answer 16 is justified.

Given that Tanya is more efficient than Sakshi. So, Tanya will take less time to complete the work.

If Tanya is 25% more efficient than Sakshi, it is not nessesary.

That Tanya will complete the work in 25% of the days less than Sakshi.

@Chandu.

It means 5:4 is known 125:100.
:: may mean equal to
20 here is the number of days taken by Sakshi and we are supposing x to be the days taken by Tanya.