There are two water tanks, A and B. Measured from the inside, the length of A water tank is 13dm, the width is 7dm, and the height is 4dm. The length of B water tank is 7dm, the width is 7dm, and the height is 5dm. Tank A is full of water and Tank B is empty. A part of the water in tank A is pumped into tank B so that the water level in both tanks is the same. What is the height of the water in the two tanks in decimeters now?
有甲、乙两个水箱，从里面量，甲水箱长为13dm、宽为7dm、高为4dm，乙水箱长为7dm、宽为7dm、高为5dm．甲水箱装满水，乙水箱空着．现将甲水箱中的一部分水抽到乙水箱中，使两个水箱中的水面高度一样．现在两个水箱中的水面高为多少分米？
<gadget id="calculator">13 * 7</gadget>
<output>91</output>

<gadget id="calculator">7 * 7</gadget>
<output>49</output>

<gadget id="calculator">91 + 49</gadget>
<output>140</output>

<gadget id="calculator">4 / 140</gadget>
<output>1/35 = around 0.028571</output>

<gadget id="calculator">13 * 7 * (1/35)</gadget>
<output>13/5 = around 2.6</output>

<result>13/5 = around 2.6</result>