Xiaolei and grandpa took a walk along the lake. They set off from a certain place by the lake at the same time and walked in the same direction. If both of them walk slowly, Xiao Ming can catch up with grandpa by walking 3 laps; if they both walk fast, Xiao Ming can catch up with grandpa by walking 7 laps. It is known that the fast walking speed of both of them is 16 meters per minute faster than the slow walking speed, so how many meters per minute is Xiaolei's fast walking speed?
小蕾和爷爷沿着湖边散步，他们从湖边某地同时出发，同向而行．如果他们两人都慢走，小明走3圈可以追上爷爷；如果他们两人都快走，小明走7圈可以追上爷爷．已知他们两人的快走的速度都比慢走每分钟多16米，那么小蕾快走的速度是每分钟多少米．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">16 * (2/3)</gadget>
<output>32/3 = around 10.666667</output>

<gadget id="calculator">16 - (32/3)</gadget>
<output>16/3 = around 5.333333</output>

<gadget id="calculator">6 / 7</gadget>
<output>6/7 = around 0.857143</output>

<gadget id="calculator">(6/7) - (2/3)</gadget>
<output>4/21 = around 0.190476</output>

<gadget id="calculator">(16/3) / (4/21)</gadget>
<output>28</output>

<result>28</result>