How has the price of a product changed if 2 times less money allows you to buy 4 times more product?

For example: let one bun cost 40 rubles. According to the condition of the problem, for half the amount, that is, 20 rubles, we can buy 4 buns. To find how much one bun is now worth, you need to divide 20 by 4.

20 ÷ 4 = 5;

Now, to find how many times the price has changed, you need the price that was before, divided by the amount that is now.

40 ÷ 5 = 8;

Answer: the price has changed 8 times.