chocolate has two packages. Each large bag weighs 1.5 kg, which is three times the weight of the small bag. The unit price of the small package is 25 yuan/pack, which is 45 yuan/pack cheaper than the large package. Find the weight of the small bag and the unit price of the big bag.
一种巧克力有两种包装．大包每包重1.5千克，是小包重量的3倍．小包的单价是25元/包，比大包便宜45元/包．求小包的重量和大包的单价．
<gadget id="calculator">25 + 45</gadget>
<output>70</output>

<result>70</result>