The cafeteria of a bilingual primary school bought 1 basket of tomatoes and 3 baskets of the same vegetables. Tomatoes weigh 50 kg and vegetables weigh 90 kg. How many kilograms does each basket of tomatoes weigh more than each basket of vegetables?
双语小学食堂买来1筐西红柿和3筐同样的青菜．西红柿重50千克，青菜共重90千克．每筐西红柿比每筐青菜重多少千克？
<gadget id="calculator">90 / 3</gadget>
<output>30</output>

<gadget id="calculator">50 - 30</gadget>
<output>20</output>

<result>20</result>