1. Person A first bought 3 sheep at an average price of $a$ dollars each at the market, and then bought 2 more sheep at an average price of $b$ dollars each. Later, he sold all the sheep to Person B at a price of $\frac{a+b}{2}$ dollars each, and found that he had lost money. The reason for the loss is ( ).
(A) $a=b$
(B) $a>b$
(C) $a<b$
(D) Irrelevant to the size of $a, b$
$-1 .(\mathrm{B})$.
$3 a+2 b>5 \times \frac{a+b}{2}$, solving yields $a>b$.