Marked price of an item is Rs 400. On purchase of 1 item discount is 6% and on purchase of 4 items discount is 24%. Rachita buys 5 items, what is the effective discount?

Marked price of item = Rs. 400

Amount saved on buying 1 item = $$\frac{6}{100} \times 400 = Rs. 24$$

Marked price of 4 items = $$4 \times 400$$ = Rs. 1600

Amount saved on buying 4 items = $$\frac{24}{100} \times 1600 = Rs. 384$$

Thus, on buying 5 items, total amount saved = 24 + 384 = Rs. 408

Total marked price of 5 items = 400 + 1600 = Rs. 2000

$$\therefore$$ Effective discount = $$\frac{408}{2000} \times 100$$

= $$\frac{204}{10} = 20.4 \%$$