Ships A and B sail towards each other at the same time from two piers 384 kilometers apart. The two ships meet on the way 8 hours later. It is known that ship A travels 21 kilometers per hour, how many kilometers per hour does ship B travel? (equation solution)
甲、乙两船由相距384千米的两个码头同时相向而行，8小时后两船在途中相遇．已知甲船每小时行21千米，那么乙船每小时行多少千米？(方程解)
<gadget id="calculator">21 * 8</gadget>
<output>168</output>

<gadget id="calculator">384 - 168</gadget>
<output>216</output>

<gadget id="calculator">216 / 8</gadget>
<output>27</output>

<result>27</result>