34)
$$vt = (v+6)(t-\frac{1}{20})$$
$$vt = vt+6t-\frac{v}{20}-\frac{6}{20} $$
$$\frac{v}{20}= 6t-\frac{6}{20} ---(1)$$
$$vt = (v-5)(t+\frac{1}{20})$$
$$vt = vt-5t+\frac{v}{20}-\frac{5}{20} $$
$$\frac{v}{20}= 5t+\frac{5}{20} ---(2)$$
$(1)-(2)$
$$0= t-\frac{11}{20} \Rightarrow t = \frac{11}{20}$$
แทนค่าใน $(2)$ ได้ $v = 60$
$$\therefore s = (60)(\frac{11}{20})= 33 km.$$
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