The price of the goods was doubled by 70%. How much has the price of the product changed?

Let us denote by c the amount of money that had to be paid in order to purchase this product before its price increase.

Then, after this product rose in price by seven tens of percent, the new price of this product was:

s + (70/100) * s = s + (7/10) * s = s + 0.7 * s = 1.7 s.

After this product has risen in price by seven tens of percent one more time, the new price of this product was:

1.7s + (70/100) * 1.7s = 1.7s + (7/10) * 1.7s = 1.7s + 0.7 * 1.7s = 1.7s + 1.19s = 2.89s.

Therefore, for 2 times the price of the goods has risen by:

100 * (2.89s – s) / s = 100 * 1.89s / s = 100 * 1.89 = 189%.

Answer: 189%.