There are 3 natural numbers a, b, c known a*b=6, b*c=15, a*c=10, then a*b*c=how much.
有3个自然数a，b，c已知a*b=6，b*c=15，a*c=10，则a*b*c=多少．
<gadget id="calculator">2 * 3 * 5</gadget>
<output>30</output>

<result>30</result>