There are two granaries, A and B. The grain stored in A is three times that of B. After A transports out 150 tons, the two store the same amount of grain. How many tons of grain is stored in warehouse B?
甲乙两个粮仓，甲仓存粮是乙仓的3倍，甲仓运出150吨后，两仓存粮一样多．乙仓存粮多少吨？
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">150 / 2</gadget>
<output>75</output>

<result>75</result>