Aptitude - Time and Work - Discussion

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.

Answer will be 25.

If the ratio taken is T:S::T:S.

125:100::X:20.

5:4::X:20 = 25.

x is no. of days taken by Tanya complete a work.

Can you explain me chain rule please?

5:4 :: 20:x.

Give a brief explain how 125:100 come?

Hey,

You can understand it like this.
As we know working efficiency of sakshi is 1/20.
And working efficiency of tanya is 25% greater.

So tanya eff = 1/20*(125/100)=1/16.

Hence time 16 days.

Here question starts with sakshi so we must take s=100.

Then 25% eff so T=75.
Then the ratio we get is 3:4.

Answer will be 15.
How can it be 16.

Can anyone please?

Sakshi working days in 20 days means 100%.
Tanya working days ?

100%-75% = 25%

So 20*25/125 = 4.
20 days - 4 = 16 days.

Sakshi's one day work is 1/20.
Tanya is 25% of sakshi it means 1/20+25%1/20.

= (1/20+25/100*1/20).
= (1/20+1/80).
= 1/16 for one day.

So 16 days to do total work.