It is known that the walking speed ratio of A and B is 2:3, and the walking speed ratio of B and C is 4:5. It is known that within 10 minutes, C walks 70 meters more than A. Then in 20 minutes, how many meters did B travel less than C?
已知甲与乙步行的速度比是2：3，乙与丙步行的速度比是4：5，已知10分钟内，丙比甲多走70米．那么在20分钟内，乙比丙少走多少米．
<gadget id="calculator">15 - 8</gadget>
<output>7</output>

<gadget id="calculator">70 / 7</gadget>
<output>10</output>

<gadget id="calculator">15 - 12</gadget>
<output>3</output>

<gadget id="calculator">10 * 3 * 2</gadget>
<output>60</output>

<result>60</result>