If C.P. of 20 identical articles is same as S.P. of 25 articles. The profit or the loss as percent is :

1. 25% loss

2. 25% profit

3. 20% loss

4. 20% profit

C.P. of 20 articles = S.P. of 25 articles

Let the C.P. of 20 articles be ₹ 100.

The C.P. of 1 article = ₹ $\dfrac{100}{20}$ = ₹ 5

The S.P. of 25 articles = The C.P. of 20 articles = ₹ 100

The S.P. of 1 article = ₹ $\dfrac{100}{25}$ = ₹ 4

(∵ C.P. is greater than S.P., means articles are sold at a loss.)

Loss = C.P. - S.P.

= ₹ (5 - 4) = ₹ 1

$\text{Loss \%} = \dfrac{\text{Loss}}{\text{C.P.}} \times 100\%\\[1em] = \dfrac{1}{5} \times 100\%\\[1em] = \dfrac{100}{5}\%\\[1em] = 20\%$

Hence,option 3 is the correct option.