C.P. of 20 articles is equal to S.P. of 16 articles. The profit or loss as percent is:

1. 25% profit

2. 25% loss

3. 20% profit

4. 20% loss

C.P. of 20 articles = S.P. of 16 articles

Let the C.P. of 20 articles be ₹ 100.

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

The S.P. of 16 articles = The C.P. of 20 articles = ₹ 100

The S.P. of 1 article = ₹ $\dfrac{100}{16}$ = ₹ 6.25

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

Profit = S.P. - C.P.

= ₹ (6.25 - 5) = ₹ 1.25

$\text{Profit \%} = \dfrac{\text{Profit}}{\text{C.P.}} \times 100\%\\[1em] = \dfrac{1.25}{5} \times 100\%\\[1em] = \dfrac{125}{5}\%\\[1em] = 25\%$

Hence,option 1 is the correct option.