The price of the product was reduced by 20% and then again reduced by 10%. How has the initial price changed?

We accept the initial price of the product before its cost reduction as 100%.

So after the first reduction, it was:

100% – 10% = 90% (from the initial).

We also accept the new cost equal to 100%.

Thus, after a new decrease by 20%, it became equal to:

100% – 20% = 80% (of the price after the first drop).

Find the final cost in relation to the initial price.

90% * 80% / 100% = 0.9 * 0.8 * 100% = 0.72 * 100% = 72%.

This means the cost has decreased by:

100% – 75% = 28%.

Answer: Decreased by 28%.