4. At the beginning of the year, the US dollar was worth 80 European cents. An expert predicted that over the course of the year, the euro's exchange rate against the ruble would increase by 8% (i.e., 1 euro would be able to buy 8% more rubles than at the beginning of the year), and the US dollar's exchange rate against the ruble would fall by 10%. If the forecast comes true, how many US cents will the euro be worth at the end of the year?
Solution. Let's choose the amount in rubles that will correspond to 1 euro (i.e., 100 European cents) at the end of the year. At the beginning of the year, the same amount corresponded to 108 European cents or $108 \cdot 100 / 80=135$ American cents. Consequently, at the end of the year, it will correspond to $135 \cdot 100 / 90=\mathbf{1 5 0}$ American cents.

Criteria. Arithmetic errors with the correct approach - 2 points are deducted.

If there is at least one "logical" error (the wrong percentage is taken, the wrong ratio is considered, etc.), the problem is considered unsolved. If the solution is completed and everything is correct except for one such error - 2 points can be given; in all other cases, 0.