Aptitude - Time and Work - Discussion

If Tanya is 25% more efficient than Sakshi, then as 25% of 20 is 5. Tanya should complete the work in 15 days not 16 days.

S can do a work in 20 days so, s=1/20;

T can do a work 25% more efficient than S.

So, T = 1/20 + (25/100*1/20).

Finally we got T = 1/16.

So 16 is the correct answer.

I am sure about my answer so don't confuse, it may be 25 or other else.

100T = 125S, 20S = 1, consider x day required for Tania.

4T = 5S, S = 1/20, Tx =1.
4T = 5*1/20 1/16x = 1.

4T = 1/4 x = 16.
T = 1/16.

So Tania required 16days to complete the work.

Why we should consider 125 and 100.

If we consider that Sakshi 100 and Tanya 75 then,

100 : 75 :: 20 : x.

= 100/75 = 20/x.

=> x = 15 days.

Let Sakshi completes the whole work = 100 days.

Then Tanya will complete it = 75 days.

Now, 100 = 20.

1 = 20/100 = 1/5.

75 = (1/5) *75 = 15 days.

So answer should be 15 days.

Nothing to do all this just simple calculation in question it is given Tanya is 25% more efficient than Sakshi which do in 20 days.

So Tanya will do 125/100*1/20 = 4 days.

Tanya does 25% efficient work. What does this mean? This means that the work that Sakshi completes is 100% and Tanya does the same work but 125%. So see efficiency as the greater percentage of work being done by Tanya 125% is greater than 100%.

For example if a does 20 units of work in 5 hrs and b does 40 units of work in 5 hrs. Then 1 hr work of A and B is 4 and 8 respectively. What does this mean? It means that B is doing more work in same no of hrs.

Now consider it as B was doing 40 units of work in 5 hrs. So what is his time for 1 unit of work? its 5/40. i.e 1/8! and similarly for A it is 1/4. So in respect of timing who is fast or efficient? Its certainly B because 1/8 is smaller than 1/4!

Hey, how come it is 16?

If Tanya takes 16 days to complete, then it means Sakshi is 25% slower than Tanya. But we have calculate Tanya's time who is 25% faster than Sakshi.

So I reckon it should be 15. Please correct me if I am wrong.

20-25%[20] = 15 days.

Sakshi is doing work with x efficiency.

Tanya is doing work with x+25% of x efficiency.

Sakshi = x work.

Tanya = x+25/100x+125x/100 = 5/4x work.

ATQ,

Sakshi is taking 20 days means x ----> 20 days.

5/4x ----> 20 x 4/5 = 16 days.