A) 5 km.
B) 35 km.
C) 40 km.
D) 45 km.
Correct Answer: B
Solution :
Let the total distance be x km. Time \[=\frac{\text{Distance}}{Speed}\] According to the question, \[\frac{10}{6}+\frac{20}{16}+\frac{x-30}{3}=4\frac{35}{60}=4\frac{7}{12}\] \[\Rightarrow \] \[\frac{5}{3}+\frac{5}{4}+\frac{x}{3}-10=\frac{55}{12}\] \[\Rightarrow \] \[\frac{x}{3}+\frac{5}{3}+\frac{5}{4}-10=\frac{55}{12}\] \[\Rightarrow \] \[\frac{x}{3}+\left( \frac{20+15-120}{12} \right)=\frac{55}{12}\] \[\Rightarrow \] \[\frac{x}{3}-\frac{85}{12}=\frac{55}{12}\] \[\Rightarrow \] \[\frac{x}{3}=\frac{85}{12}+\frac{55}{12}=\frac{140}{12}\] \[\Rightarrow \] \[x=\frac{140}{12}\times 3=35\,km.\]You need to login to perform this action.
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