Step-by-step explanation:

Let's assume Rachna's weight to be 'x'.

Then, according to the problem, Ruchi's weight is 25% of Rachna's weight, which can be expressed as:

Ruchi's weight = 25% of x = (25/100)x = (1/4)x

Also, Ruchi's weight is 40% of Rekha's weight, which can be expressed as:

Ruchi's weight = 40% of Rekha's weight = (40/100)Rekha's weight = (2/5)Rekha's weight

Now, we need to find the percentage of Rekha's weight that is Rachna's weight.

Let's assume this percentage to be 'y'.

Then, we can write:

Rachna's weight = y% of Rekha's weight = (y/100)Rekha's weight

We know that Ruchi's weight is equal to (1/4)x and (2/5)Rekha's weight. Therefore, we can write:

(1/4)x = (2/5)Rekha's weight

Simplifying this equation, we get:

Rekha's weight = (5/2) * (1/4) * x = (5/8) x

Now, we can substitute this value of Rekha's weight in the equation for Rachna's weight:

Rachna's weight = y% of (5/8)x

Simplifying this equation, we get:

Rachna's weight = (5y/8) x

We know that Ruchi's weight is 25% of Rachna's weight. Therefore, we can write:

(1/4)x = 25% of x = (25/100)x = (5/20)x

Simplifying this equation, we get:

(1/4)x = (5/20)x

Multiplying both sides by 20, we get:

5x = 20 * (1/4) x = 5x

Therefore, we can conclude that Rachna's weight is equal to Ruchi's weight.

Hence, the percentage of Rekha's weight that is Rachna's weight is 100%.