3.10 Two skins with a total cost of 2250 rubles were sold at an auction with a profit of $40 \%$. What is the cost of each skin if a profit of $25 \%$ was made on the first one, and a loss of $-50 \%$ on the second one?
3.10 Let $x$ (rubles) be the cost of the first pelt, then $2250-x$ (rubles) is the cost of the second pelt. After selling, the first pelt was sold for $1.25 x$ (rubles), and the second for $1.5(2250-x)$ (rubles). According to the condition, we set up the equation

$1.25 x + 1.5(2250 - x) = 1.4 \cdot 2250$,

from which $x = 900$ (rubles); hence, $2250 - x = 1350$ (rubles).

Answer: 900 and 1350 rubles.