professional sericulture household raised 210 silkworm seeds the year before last, and raised 135 more than the year before last year. Last year, they collected 21,390 kilograms of silkworm cocoons. How many kilograms of silkworm cocoons were harvested on average per silkworm seed?
一个养蚕专业户，前年养了210张蚕子，去年比前年多养了135张，去年收蚕茧21390千克，平均每张蚕子收蚕茧多少千克？
<gadget id="calculator">210 + 135</gadget>
<output>345</output>

<gadget id="calculator">21_390 / 345</gadget>
<output>62</output>

<result>62</result>