Aptitude - Time and Work - Discussion

(SAKSHI) 125%=20,
(TANYA) 100%= x,
125*x = 20*100,
x = (20*100)/125,
x = 16 days.

Sakshi = 120% of 20 days.
Tanya = 100% of x days.
X= 20*100/120,
X= 20*4/5.
X=80/4.
X= 16 days.

Sakshi completed the task in 20.
Tanya is 25% more efficient than Sakshi,
So 20/25= 0.8,
0.8 * 20 = 16,
So, Tanya takes 16 days to complete the whole task.

@Oakley.

Efficiency: When we say Tanya is 25% more efficient than Sakshi, it means Tanya can do 25% more work in the same amount of time compared to Sakshi. This directly affects the number of days she will take to complete the work.

Efficiency does not directly translate to days: If Tanya is 25% more efficient, it doesn't mean she will take 25% fewer days. Instead, her work rate is 25% higher.

Let us solve it easily:

So, Tanya is 25% more efficient than Shaksi which means Tanya is 100% then Sakshi will be 125%
Now: Sakshi:125--> 20 days
Tanya :100-->x.
By cross multiply(x)-->x=20*100/125.
= 16days.

Yes, you are correct @Okley.

Why can't 15 be the answer?
25%of 20=5 subtracts from 20 then gets 15, right?

Tanaya is - 25% more efficient than of (Sakshi).

So let's assume,

Sakshi takes 20 days to travel 2000km with a speed of 100km/ day
So Tania should take, X days to travel 2000km with the speed of 125% of (100km/day)

So speed should be, 100/100 * 25.
So time would be, 2000/125 = 16 days.

@All.

Here Tanya is 25% more efficient than Sakshi. So why can't we take Tanya as 100 and Sakshi as 75. It can be understood from the basic concept of percentages that if A is 25% more than B, B is how much percent less than A and that will never be 25.

Let B=100 => A=125. Difference= 25. How much is B less than A = (25/125)*100 = 20%. The change is to be taken from A i.e 125 and not 100.

Similarly, if Tanya is 25% more efficient than Sakshi, then Sakshi is 20% less efficient than Tanya and not 25%.

So going by this, if you take 80 instead of 75, you will get the same answer which is also the only correct answer.

Sakshi can do a piece of work in 20 days and Tanya is 25% more efficient than Sakshi that means

125% of Work by Sakshi in ------------> 20 days.
100% of Work by Tanya ---------------> x.


By Cross Multiplication we get;

125% * x = 100% * 20,
=> (125/100) * x = (100/100) * 20,
=> x = (100/125) * (100/100) * 20,

After Cancellation You'll get Result as 16 days.

Solve by the Trick:

100 * M/100 + X.
Here, M = day.
X= efficiency.
Therefore:

100 * 20/100 + 25,
2000/125,
16 days.