A box of biscuits weighs 2.1 kilograms. After eating half of the biscuits, the weight of the box is 1.15 kilograms. How many kilograms of biscuits are there in the box?
一盒饼干连盒重2.1千克，吃掉一半饼干后，连盒重1.15千克，盒中原来有饼干多少千克．
<gadget id="calculator">2.1 - 1.15</gadget>
<output>0.95</output>

<gadget id="calculator">0.95 * 2</gadget>
<output>1.9</output>

<result>1.9</result>